diff --git a/ChangeLog b/ChangeLog
index 4506b6db12..26050a650e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Fri Oct 30 06:15:50 2015  Koichi Sasada  <ko1@atdot.net>
+
+	* vm.c: add ifndef guard for VM_CHECK_MODE.
+
 Fri Oct 30 06:13:10 2015  Koichi Sasada  <ko1@atdot.net>
 
 	* vm_insnhelper.c (vm_check_frame_detail): should require me for
diff --git a/vm.c b/vm.c
index 279c1ea8e6..7c4d6fe2c1 100644
--- a/vm.c
+++ b/vm.c
@@ -8,7 +8,9 @@
 
 **********************************************************************/
 
+#ifndef VM_CHECK_MODE
 #define VM_CHECK_MODE 0
+#endif
 
 #include "internal.h"
 #include "ruby/vm.h"