diff --git a/ChangeLog b/ChangeLog
index 90f7c1f57e..b8130f5ea8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Mon Jun 25 20:18:44 2007  NAKAMURA Usaku  <usa@ruby-lang.org>
+
+	* gc.c (RVALUE): in RVALUE and RBasic, flags must be the same type.
+
 Mon Jun 25 18:02:55 2007  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* ext/pty/extconf.rb: skip wince and win64.
diff --git a/gc.c b/gc.c
index 10cb5c6a3d..4360a535f2 100644
--- a/gc.c
+++ b/gc.c
@@ -95,7 +95,7 @@ int ruby_gc_debug_indent = 0;
 typedef struct RVALUE {
     union {
 	struct {
-	    unsigned long flags;	/* always 0 for freed obj */
+	    VALUE flags;		/* always 0 for freed obj */
 	    struct RVALUE *next;
 	} free;
 	struct RBasic  basic;