diff --git a/ChangeLog b/ChangeLog
index 7ade41d42f..0b5fcd475e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Thu Mar 19 16:12:01 2015  Koichi Sasada  <ko1@atdot.net>
+
+	* gc.c (newobj_of): fix RGENGC_OLD_NEWOBJ_CHECK logics.
+	  * skip on incremental marking because not sure what happen :p
+	  * rb_gc_writebarrier_remember() is enough to mark children.
+
 Thu Mar 19 16:08:42 2015  Koichi Sasada  <ko1@atdot.net>
 
 	* gc.c (rb_copy_wb_protected_attribute): need demote for old objects.
diff --git a/gc.c b/gc.c
index 8b1493fc5e..44373a4314 100644
--- a/gc.c
+++ b/gc.c
@@ -1748,7 +1748,8 @@ newobj_of(VALUE klass, VALUE flags, VALUE v1, VALUE v2, VALUE v3)
     {
 	static int newobj_cnt = RGENGC_OLD_NEWOBJ_CHECK;
 
-	if (flags & FL_WB_PROTECTED &&   /* do not promote WB unprotected objects */
+	if (!is_incremental_marking(objspace) &&
+	    flags & FL_WB_PROTECTED &&   /* do not promote WB unprotected objects */
 	    ! RB_TYPE_P(obj, T_ARRAY)) { /* array.c assumes that allocated objects are new */
 	    if (--newobj_cnt == 0) {
 		newobj_cnt = RGENGC_OLD_NEWOBJ_CHECK;
@@ -1756,10 +1757,7 @@ newobj_of(VALUE klass, VALUE flags, VALUE v1, VALUE v2, VALUE v3)
 		gc_mark_set(objspace, obj);
 		RVALUE_AGE_SET_OLD(objspace, obj);
 
-		if (is_pointer_to_heap(objspace, (void *)klass)) RB_OBJ_WRITTEN(obj, Qundef, klass);
-		if (is_pointer_to_heap(objspace, (void *)v1))    RB_OBJ_WRITTEN(obj, Qundef, v1);
-		if (is_pointer_to_heap(objspace, (void *)v2))    RB_OBJ_WRITTEN(obj, Qundef, v2);
-		if (is_pointer_to_heap(objspace, (void *)v3))    RB_OBJ_WRITTEN(obj, Qundef, v3);
+		rb_gc_writebarrier_remember(obj);
 	    }
 	}
     }