diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5ccf8b8f8..07112b07b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -2,7 +2,7 @@ cmake_minimum_required(VERSION 2.8.8)
 project(libchewing)
 
 # Update configure.ac if LIBCHEWING_VERSION is changed.
-set(LIBCHEWING_VERSION 0.5.0)
+set(LIBCHEWING_VERSION 0.5.1)
 set(PACKAGE_VERSION ${LIBCHEWING_VERSION})
 # Update configure.ac if LIBCHEWING_BINARY_VERSION is changed.
 set(LIBCHEWING_BINARY_VERSION 1.0.0)
diff --git a/configure.ac b/configure.ac
index 88a870205..e4393cebc 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3,7 +3,7 @@
 AC_PREREQ([2.65])
 
 # Update CMakeLists.txt if version is changed.
-AC_INIT([libchewing],[0.5.0],[chewing-devel@googlegroups.com])
+AC_INIT([libchewing],[0.5.1],[chewing-devel@googlegroups.com])
 AC_CONFIG_AUX_DIR([build-aux])
 AC_CONFIG_SRCDIR([src/chewingio.c])
 AC_CONFIG_MACRO_DIR([m4])