diff --git a/README.md b/README.md
index 75c9cf8..e557319 100644
--- a/README.md
+++ b/README.md
@@ -44,7 +44,7 @@ PinIt 이 추구하는 핵심 목적은 다음 세 가지입니다.
 사용자가 실제로 수행하는 “할 일/작업”에 해당합니다.
 
 * 일정 타입 (집중 작업, 행정 작업, 짧은 업무 등)
-* 중요도 / 긴급도
+* 중요도 / 난이도
 * 예상 소요 시간
 * 마감 일자
 * 현재 상태 (예정, 진행 중, 완료 등)
@@ -78,7 +78,7 @@ PinIt 이 추구하는 핵심 목적은 다음 세 가지입니다.
 
 * **일정 생성**
 
-    * 일정의 기본 정보(제목, 타입, 마감일, 중요도, 긴급도, 예상 소요 시간 등)를 입력받아 생성
+    * 일정의 기본 정보(제목, 타입, 마감일, 중요도, 난이도, 예상 소요 시간 등)를 입력받아 생성
 * **일정 조회**
 
     * 특정 날짜의 일정 목록 조회
diff --git a/src/main/java/me/gg/pinit/pinittask/application/schedule/dto/ScheduleDependencyAdjustCommand.java b/src/main/java/me/gg/pinit/pinittask/application/schedule/dto/ScheduleDependencyAdjustCommand.java
index da8efdd..674626b 100644
--- a/src/main/java/me/gg/pinit/pinittask/application/schedule/dto/ScheduleDependencyAdjustCommand.java
+++ b/src/main/java/me/gg/pinit/pinittask/application/schedule/dto/ScheduleDependencyAdjustCommand.java
@@ -14,34 +14,34 @@
 import java.util.Objects;
 
 public class ScheduleDependencyAdjustCommand {
-    private Long scheduleId;
+    private final Long scheduleId;
     @Getter
-    private Long ownerId;
+    private final Long ownerId;
     @Getter
-    private String title;
+    private final String title;
     @Getter
-    private String description;
+    private final String description;
     @Getter
-    private ZonedDateTime deadline;
+    private final ZonedDateTime deadline;
     @Getter
-    private Integer importance;
+    private final Integer importance;
     @Getter
-    private Integer urgency;
+    private final Integer difficulty;
     @Getter
-    private TaskType taskType;
+    private final TaskType taskType;
     @Getter
-    private ZonedDateTime date;
-    private List<DependencyDto> removeDependencies;
-    private List<DependencyDto> addDependencies;
+    private final ZonedDateTime date;
+    private final List<DependencyDto> removeDependencies;
+    private final List<DependencyDto> addDependencies;
 
-    public ScheduleDependencyAdjustCommand(Long scheduleId, Long ownerId, String title, String description, ZonedDateTime deadline, Integer importance, Integer urgency, TaskType taskType, ZonedDateTime date, List<DependencyDto> removeDependencies, List<DependencyDto> addDependencies) {
+    public ScheduleDependencyAdjustCommand(Long scheduleId, Long ownerId, String title, String description, ZonedDateTime deadline, Integer importance, Integer difficulty, TaskType taskType, ZonedDateTime date, List<DependencyDto> removeDependencies, List<DependencyDto> addDependencies) {
         this.scheduleId = scheduleId;
         this.ownerId = ownerId;
         this.title = title;
         this.description = description;
         this.deadline = deadline;
         this.importance = importance;
-        this.urgency = urgency;
+        this.difficulty = difficulty;
         this.taskType = taskType;
         this.date = date;
         this.removeDependencies = removeDependencies;
@@ -59,7 +59,7 @@ public Schedule getTemporalSchedule() {
                 description,
                 date,
                 new TemporalConstraint(deadline, Duration.ZERO, taskType),
-                new ImportanceConstraint(importance, urgency)
+                new ImportanceConstraint(importance, difficulty)
         );
     }
 
@@ -69,7 +69,7 @@ public SchedulePatch getSchedulePatch() {
                 .setDescription(description)
                 .setDeadline(deadline)
                 .setImportance(importance)
-                .setUrgency(urgency)
+                .setDifficulty(difficulty)
                 .setTaskType(taskType)
                 .setDate(date);
     }
diff --git a/src/main/java/me/gg/pinit/pinittask/domain/schedule/model/Schedule.java b/src/main/java/me/gg/pinit/pinittask/domain/schedule/model/Schedule.java
index 407723d..4c2dd1d 100644
--- a/src/main/java/me/gg/pinit/pinittask/domain/schedule/model/Schedule.java
+++ b/src/main/java/me/gg/pinit/pinittask/domain/schedule/model/Schedule.java
@@ -107,7 +107,7 @@ public boolean isSuspended() {
     public void patch(SchedulePatch patch) {
         checkStateIsNotCompleted();
         patch.importance().ifPresent(this::changeImportance);
-        patch.urgency().ifPresent(this::changeUrgency);
+        patch.difficulty().ifPresent(this::changeDifficulty);
         patch.title().ifPresent(this::setTitle);
         patch.description().ifPresent(this::setDescription);
         patch.deadline().ifPresent(this::changeDeadline);
@@ -149,8 +149,8 @@ public void changeImportance(int newImportance) {
         this.importanceConstraint = this.importanceConstraint.changeImportance(newImportance);
     }
 
-    public void changeUrgency(int newUrgency) {
-        this.importanceConstraint = this.importanceConstraint.changeUrgency(newUrgency);
+    public void changeDifficulty(int newDifficulty) {
+        this.importanceConstraint = this.importanceConstraint.changeDifficultyLevel(newDifficulty);
     }
 
     public String getState() {
diff --git a/src/main/java/me/gg/pinit/pinittask/domain/schedule/patch/SchedulePatch.java b/src/main/java/me/gg/pinit/pinittask/domain/schedule/patch/SchedulePatch.java
index 1164992..3d0c594 100644
--- a/src/main/java/me/gg/pinit/pinittask/domain/schedule/patch/SchedulePatch.java
+++ b/src/main/java/me/gg/pinit/pinittask/domain/schedule/patch/SchedulePatch.java
@@ -10,7 +10,7 @@ public final class SchedulePatch {
     private String description;
     private ZonedDateTime deadline;
     private Integer importance;
-    private Integer urgency;
+    private Integer difficulty;
     private TaskType taskType;
     private ZonedDateTime date;
 
@@ -34,8 +34,8 @@ public SchedulePatch setImportance(Integer v) {
         return this;
     }
 
-    public SchedulePatch setUrgency(Integer v) {
-        this.urgency = v;
+    public SchedulePatch setDifficulty(Integer v) {
+        this.difficulty = v;
         return this;
     }
 
@@ -65,8 +65,8 @@ public Optional<Integer> importance() {
         return Optional.ofNullable(importance);
     }
 
-    public Optional<Integer> urgency() {
-        return Optional.ofNullable(urgency);
+    public Optional<Integer> difficulty() {
+        return Optional.ofNullable(difficulty);
     }
 
     public Optional<TaskType> taskType() {
@@ -79,7 +79,7 @@ public Optional<ZonedDateTime> date() {
 
     public boolean isEmpty() {
         return title == null && description == null && deadline == null
-                && importance == null && urgency == null && taskType == null && date == null;
+                && importance == null && difficulty == null && taskType == null && date == null;
     }
 }
 
diff --git a/src/main/java/me/gg/pinit/pinittask/domain/schedule/vo/ImportanceConstraint.java b/src/main/java/me/gg/pinit/pinittask/domain/schedule/vo/ImportanceConstraint.java
index cda6e28..550109c 100644
--- a/src/main/java/me/gg/pinit/pinittask/domain/schedule/vo/ImportanceConstraint.java
+++ b/src/main/java/me/gg/pinit/pinittask/domain/schedule/vo/ImportanceConstraint.java
@@ -5,48 +5,59 @@
 import lombok.Getter;
 
 import java.util.Objects;
+import java.util.Set;
 
 @Getter
 @Embeddable
 public class ImportanceConstraint {
+    private static final Set<Integer> VALID_DIFFICULTY_LEVELS = Set.of(1, 2, 3, 5, 8, 13, 21);
+
     @Column(name = "importance_level")
     private int importance;
 
-    @Column(name = "urgency_level")
-    private int urgency;
+    @Column(name = "difficulty_level")
+    private int difficulty;
 
     protected ImportanceConstraint() {}
 
-    public ImportanceConstraint(int importance, int urgency) {
+    public ImportanceConstraint(int importance, int difficulty) {
+        validateImportanceLevel(importance);
         this.importance = importance;
-        this.urgency = urgency;
+        validateDifficultyLevel(difficulty);
+        this.difficulty = difficulty;
     }
 
     public ImportanceConstraint changeImportance(int importance) {
-        validateLevel(importance);
-        return new ImportanceConstraint(importance, this.urgency);
+        validateImportanceLevel(importance);
+        return new ImportanceConstraint(importance, this.difficulty);
     }
 
-    public ImportanceConstraint changeUrgency(int urgency) {
-        validateLevel(urgency);
-        return new ImportanceConstraint(this.importance, urgency);
+    public ImportanceConstraint changeDifficultyLevel(int difficulty) {
+        validateDifficultyLevel(difficulty);
+        return new ImportanceConstraint(this.importance, difficulty);
     }
 
     @Override
     public boolean equals(Object o) {
         if (o == null || getClass() != o.getClass()) return false;
         ImportanceConstraint that = (ImportanceConstraint) o;
-        return importance == that.importance && urgency == that.urgency;
+        return importance == that.importance && difficulty == that.difficulty;
     }
 
     @Override
     public int hashCode() {
-        return Objects.hash(importance, urgency);
+        return Objects.hash(importance, difficulty);
     }
 
-    private void validateLevel(int level) {
+    private void validateImportanceLevel(int level) {
         if (level < 1 || level > 9) {
-            throw new IllegalArgumentException("중요도와 긴급도 레벨은 1에서 9 사이여야 합니다.");
+            throw new IllegalArgumentException("중요도 레벨은 1에서 9 사이여야 합니다.");
+        }
+    }
+
+    private void validateDifficultyLevel(int difficulty) {
+        if (!VALID_DIFFICULTY_LEVELS.contains(difficulty)) {
+            throw new IllegalArgumentException("난이도 레벨은 1, 2, 3, 5, 8, 13, 21 중 하나여야 합니다.");
         }
     }
 }
diff --git a/src/main/java/me/gg/pinit/pinittask/interfaces/dto/ScheduleRequest.java b/src/main/java/me/gg/pinit/pinittask/interfaces/dto/ScheduleRequest.java
index a3b418c..23941e6 100644
--- a/src/main/java/me/gg/pinit/pinittask/interfaces/dto/ScheduleRequest.java
+++ b/src/main/java/me/gg/pinit/pinittask/interfaces/dto/ScheduleRequest.java
@@ -6,8 +6,8 @@
 import jakarta.validation.constraints.Min;
 import jakarta.validation.constraints.NotBlank;
 import jakarta.validation.constraints.NotNull;
-import me.gg.pinit.pinittask.application.schedule.dto.DependencyDto;
 import me.gg.pinit.pinittask.application.datetime.DateTimeUtils;
+import me.gg.pinit.pinittask.application.schedule.dto.DependencyDto;
 import me.gg.pinit.pinittask.application.schedule.dto.ScheduleDependencyAdjustCommand;
 import me.gg.pinit.pinittask.domain.schedule.model.TaskType;
 
@@ -33,9 +33,9 @@ public record ScheduleRequest(
         Integer importance,
         @NotNull
         @Min(1)
-        @Max(9)
-        @Schema(description = "긴급도 (1~9)", example = "7")
-        Integer urgency,
+        @Max(21)
+        @Schema(description = "난이도 (21 이하의 피보나치 수)", example = "3")
+        Integer difficulty,
         @NotNull
         @Schema(description = "작업 유형", example = "TASK")
         TaskType taskType,
@@ -58,7 +58,7 @@ public ScheduleDependencyAdjustCommand toCommand(Long scheduleId, Long ownerId,
                 description,
                 dateTimeUtils.toZonedDateTime(deadline.dateTime(), deadline.zoneId()),
                 importance,
-                urgency,
+                difficulty,
                 taskType,
                 dateTimeUtils.toZonedDateTime(date.dateTime(), date.zoneId()),
                 remove,
diff --git a/src/main/java/me/gg/pinit/pinittask/interfaces/dto/ScheduleResponse.java b/src/main/java/me/gg/pinit/pinittask/interfaces/dto/ScheduleResponse.java
index bfce604..396a675 100644
--- a/src/main/java/me/gg/pinit/pinittask/interfaces/dto/ScheduleResponse.java
+++ b/src/main/java/me/gg/pinit/pinittask/interfaces/dto/ScheduleResponse.java
@@ -23,8 +23,8 @@ public record ScheduleResponse(
         DateTimeWithZone deadline,
         @Schema(description = "중요도")
         int importance,
-        @Schema(description = "긴급도")
-        int urgency,
+        @Schema(description = "난이도")
+        int difficulty,
         @Schema(description = "누적 작업 시간")
         Duration duration,
         @Schema(description = "현재 상태")
@@ -42,7 +42,7 @@ public static ScheduleResponse from(Schedule schedule) {
                 DateTimeWithZone.from(schedule.getDesignatedStartTime()),
                 DateTimeWithZone.from(temporal.getDeadline()),
                 importanceConstraint.getImportance(),
-                importanceConstraint.getUrgency(),
+                importanceConstraint.getDifficulty(),
                 history.getElapsedTime(),
                 schedule.getState()
         );
diff --git a/src/test/java/me/gg/pinit/pinittask/application/schedule/service/ScheduleAdjustmentServiceTest.java b/src/test/java/me/gg/pinit/pinittask/application/schedule/service/ScheduleAdjustmentServiceTest.java
index a28d432..37e49e2 100644
--- a/src/test/java/me/gg/pinit/pinittask/application/schedule/service/ScheduleAdjustmentServiceTest.java
+++ b/src/test/java/me/gg/pinit/pinittask/application/schedule/service/ScheduleAdjustmentServiceTest.java
@@ -45,7 +45,7 @@ void createSchedule() {
                 "DESC",
                 now.plusHours(4),
                 5,
-                6,
+                5,
                 TaskType.DEEP_WORK,
                 now,
                 Collections.emptyList(),
@@ -116,7 +116,7 @@ void adjustSchedule() {
         assertEquals("NEW_TITLE", patch.title().orElse(null));
         assertEquals("NEW_DESC", patch.description().orElse(null));
         assertEquals(9, patch.importance().orElse(-1));
-        assertEquals(3, patch.urgency().orElse(-1));
+        assertEquals(3, patch.difficulty().orElse(-1));
         assertEquals(TaskType.QUICK_TASK, patch.taskType().orElse(null));
 
         verify(dependencyService).deleteAll(anyList());
diff --git a/src/test/java/me/gg/pinit/pinittask/domain/schedule/vo/ImportanceConstraintTest.java b/src/test/java/me/gg/pinit/pinittask/domain/schedule/vo/ImportanceConstraintTest.java
index 2a4d506..4823a53 100644
--- a/src/test/java/me/gg/pinit/pinittask/domain/schedule/vo/ImportanceConstraintTest.java
+++ b/src/test/java/me/gg/pinit/pinittask/domain/schedule/vo/ImportanceConstraintTest.java
@@ -2,7 +2,6 @@
 
 import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
-import org.mockito.internal.matchers.Equals;
 
 import static org.junit.jupiter.api.Assertions.*;
 
@@ -26,4 +25,26 @@ class ImportanceConstraintTest {
         //then
         assertNotEquals(constraint, differentConstraint, "ImportanceConstraint 객체가 서로 다른 값으로 생성되었을 때 equals 메서드는 false를 반환해야 합니다.");
     }
-}
\ No newline at end of file
+
+    @DisplayName("허용되지 않은 난이도 레벨로 생성 시 예외가 발생해야 한다")
+    @Test
+    void DifficultyLevel_허용되지_않은_값이라면_예외_발생() {
+        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class,
+                () -> new ImportanceConstraint(1, 4),
+                "허용되지 않은 난이도 레벨로 ImportanceConstraint를 생성하면 IllegalArgumentException이 발생해야 합니다.");
+
+        assertEquals("난이도 레벨은 1, 2, 3, 5, 8, 13, 21 중 하나여야 합니다.", exception.getMessage());
+    }
+
+    @DisplayName("허용되지 않은 난이도 레벨로 변경 시 예외가 발생해야 한다")
+    @Test
+    void changeDifficultyLevel_허용되지_않은_값이라면_예외_발생() {
+        ImportanceConstraint constraint = new ImportanceConstraint(1, 3);
+
+        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class,
+                () -> constraint.changeDifficultyLevel(0),
+                "허용되지 않은 난이도 레벨로 변경을 시도하면 IllegalArgumentException이 발생해야 합니다.");
+
+        assertEquals("난이도 레벨은 1, 2, 3, 5, 8, 13, 21 중 하나여야 합니다.", exception.getMessage());
+    }
+}