diff --git a/ChangeLog b/ChangeLog
index ae7b2596ad..d346ba0940 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Fri Dec 20 17:52:50 2013  Koichi Sasada  <ko1@atdot.net>
+
+	* vm_method.c: check definition of
+	  GLOBAL_METHOD_CACHE_SIZE and GLOBAL_METHOD_CACHE_MASK.
+
 Fri Dec 20 17:03:10 2013  Koichi Sasada  <ko1@atdot.net>
 
 	* include/ruby/ruby.h: rename OBJ_WRITE and OBJ_WRITTEN into
diff --git a/vm_method.c b/vm_method.c
index 737cd26956..fce8add6ef 100644
--- a/vm_method.c
+++ b/vm_method.c
@@ -2,8 +2,13 @@
  * This file is included by vm.c
  */
 
+#ifndef GLOBAL_METHOD_CACHE_SIZE
 #define GLOBAL_METHOD_CACHE_SIZE 0x800
+#endif
+#ifndef GLOBAL_METHOD_CACHE_MASK
 #define GLOBAL_METHOD_CACHE_MASK 0x7ff
+#endif
+
 #define GLOBAL_METHOD_CACHE_KEY(c,m) ((((c)>>3)^(m))&GLOBAL_METHOD_CACHE_MASK)
 #define GLOBAL_METHOD_CACHE(c,m) (global_method_cache + GLOBAL_METHOD_CACHE_KEY(c,m))
 #include "method.h"