diff --git a/ChangeLog b/ChangeLog
index 9e796781e2..c07cced27d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Fri Jun 21 12:35:35 2013  Koichi Sasada  <ko1@atdot.net>
+
+	* gc.c: RGENGC_CHECK_MODE should be 0.
+
 Fri Jun 21 11:18:25 2013  Koichi Sasada  <ko1@atdot.net>
 
 	* gc.c (gc_marks_body): fix to get `th' in this function.
diff --git a/gc.c b/gc.c
index 253a75ea2d..f8b6305647 100644
--- a/gc.c
+++ b/gc.c
@@ -126,7 +126,7 @@ void rb_gcdebug_print_obj_condition(VALUE obj);
  * 3: show all references
  */
 #ifndef RGENGC_CHECK_MODE
-#define RGENGC_CHECK_MODE  2
+#define RGENGC_CHECK_MODE  0
 #endif
 
 /* RGENGC_PROFILE