diff --git a/ChangeLog b/ChangeLog
index f988ad5175..84a527617c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Mon Sep 14 10:44:47 2009  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* include/ruby/ruby.h (RB_TYPE_P): should not use BUILTIN_TYPE for
+	  special constants.
+
 Mon Sep 14 10:08:19 2009  NARUSE, Yui  <naruse@ruby-lang.org>
 
 	* string.c (rb_str_inspect): use rb_enc_mbc_to_codepoint
diff --git a/include/ruby/ruby.h b/include/ruby/ruby.h
index a9cb9b0fa3..2d6ba66e5c 100644
--- a/include/ruby/ruby.h
+++ b/include/ruby/ruby.h
@@ -1258,7 +1258,7 @@ rb_type(VALUE obj)
 	((type) == T_NIL) ? ((obj) == Qnil) : \
 	((type) == T_UNDEF) ? ((obj) == Qundef) : \
 	((type) == T_SYMBOL) ? SYMBOL_P(obj) : \
-	(BUILTIN_TYPE(obj) == (type)))
+	(!SPECIAL_CONST_P(obj) && BUILTIN_TYPE(obj) == (type)))
 
 #ifdef __GNUC__
 #define rb_type_p(obj, type) \