diff --git a/.github/workflows/actionlint.yml b/.github/workflows/actionlint.yml
index beb4084..39af8f0 100644
--- a/.github/workflows/actionlint.yml
+++ b/.github/workflows/actionlint.yml
@@ -29,7 +29,7 @@ jobs:
       actions: read
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
 
       - name: Lint workflow files
         shell: bash
@@ -37,7 +37,7 @@ jobs:
           bash <(curl -LsS --retry 2 https://raw.githubusercontent.com/rhysd/actionlint/main/scripts/download-actionlint.bash)
           ./actionlint -color
 
-      - uses: 8398a7/action-slack@v3
+      - uses: 8398a7/action-slack@28ba43ae48961b90635b50953d216767a6bea486 # v3
         with:
           status: ${{ job.status }}
           fields: repo,message,job,pullRequest
diff --git a/.github/workflows/conflibot.yml b/.github/workflows/conflibot.yml
index e5b4d1e..6e99dd0 100644
--- a/.github/workflows/conflibot.yml
+++ b/.github/workflows/conflibot.yml
@@ -24,8 +24,8 @@ jobs:
       checks: write
 
     steps:
-      - uses: actions/checkout@v4
-      - uses: wktk/conflibot@v1
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
+      - uses: wktk/conflibot@4881912dc3fe459059127d667251d5b324622299 # v1
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}
           exclude: ""
diff --git a/.github/workflows/metacheck.yml b/.github/workflows/metacheck.yml
index 9330037..28b0e62 100644
--- a/.github/workflows/metacheck.yml
+++ b/.github/workflows/metacheck.yml
@@ -25,14 +25,14 @@ jobs:
       actions: read
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
         with:
           submodules: false
           lfs: false
 
-      - uses: DeNA/unity-meta-check@v4
+      - uses: DeNA/unity-meta-check@a2e35e2c0b652031facd143db6f0a438b49de38a # v4
 
-      - uses: 8398a7/action-slack@v3
+      - uses: 8398a7/action-slack@28ba43ae48961b90635b50953d216767a6bea486 # v3
         with:
           status: ${{ job.status }}
           fields: repo,message,job,pullRequest
diff --git a/.github/workflows/test-integration.yml b/.github/workflows/test-integration.yml
index 8d5fb57..a506005 100644
--- a/.github/workflows/test-integration.yml
+++ b/.github/workflows/test-integration.yml
@@ -54,12 +54,12 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
         with:
           submodules: false
           lfs: false
 
-      - uses: buildjet/cache@v4
+      - uses: buildjet/cache@3e70d19e31d6a8030aeddf6ed8dbe601f94d09f4 # v4
         with:
           path: Library
           key: Library-linux-${{ matrix.unityVersion }}-${{ github.ref }}
@@ -79,7 +79,7 @@ jobs:
         run: echo "secret_key=UNITY_LICENSE_$(echo ${{ matrix.unityVersion }} | cut -c 1-4)" >> "$GITHUB_ENV"
 
       - name: Run tests
-        uses: game-ci/unity-test-runner@v4
+        uses: game-ci/unity-test-runner@0ff419b913a3630032cbe0de48a0099b5a9f0ed9 # v4
         with:
           githubToken: ${{ secrets.GITHUB_TOKEN }}
           unityVersion: ${{ matrix.unityVersion }}  # Default is `auto`
@@ -95,7 +95,7 @@ jobs:
         id: test
 
       - name: Upload test results
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4
         with:
           name: TestResults-Unity${{ matrix.unityVersion }}-${{ matrix.testMode }}
           path: |
@@ -112,7 +112,7 @@ jobs:
       actions: read
 
     steps:
-      - uses: Gamesight/slack-workflow-status@v1.3.0
+      - uses: Gamesight/slack-workflow-status@68bf00d0dbdbcb206c278399aa1ef6c14f74347a # v1.3.0
         with:
           repo_token: ${{ secrets.GITHUB_TOKEN }}
           slack_webhook_url: ${{ secrets.SLACK_WEBHOOK_URL }}
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index daa152f..c08470f 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -57,12 +57,12 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
         with:
           submodules: false
           lfs: false
 
-      - uses: actions/cache@v4
+      - uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684 # v4
         with:
           path: Library
           key: Library-linux-${{ matrix.unityVersion }}-${{ github.ref }}
@@ -82,7 +82,7 @@ jobs:
         run: echo "secret_key=UNITY_LICENSE_$(echo ${{ matrix.unityVersion }} | cut -c 1-4)" >> "$GITHUB_ENV"
 
       - name: Run tests
-        uses: game-ci/unity-test-runner@v4
+        uses: game-ci/unity-test-runner@0ff419b913a3630032cbe0de48a0099b5a9f0ed9 # v4
         with:
           githubToken: ${{ secrets.GITHUB_TOKEN }}
           unityVersion: ${{ matrix.unityVersion }}  # Default is `auto`
@@ -102,11 +102,11 @@ jobs:
         if: ${{ matrix.octocov }}
 
       - name: Run octocov
-        uses: k1LoW/octocov-action@v1
+        uses: k1LoW/octocov-action@73d561f65d59e66899ed5c87e4621a913b5d5c20 # v1
         if: ${{ matrix.octocov }}
 
       - name: Upload test results
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4
         with:
           name: TestResults-Unity${{ matrix.unityVersion }}-${{ matrix.testMode }}
           path: |
@@ -123,7 +123,7 @@ jobs:
       actions: read
 
     steps:
-      - uses: Gamesight/slack-workflow-status@v1.3.0
+      - uses: Gamesight/slack-workflow-status@68bf00d0dbdbcb206c278399aa1ef6c14f74347a # v1.3.0
         with:
           repo_token: ${{ secrets.GITHUB_TOKEN }}
           slack_webhook_url: ${{ secrets.SLACK_WEBHOOK_URL }}