diff --git a/ChangeLog b/ChangeLog
index b4e606fd1d..13e76d663f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Thu Dec 15 17:40:28 2011  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* error.c (rb_check_type): fix typo.
+
 Thu Dec 15 14:48:35 2011  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* ext/strscan/strscan.c: use typed data with
diff --git a/error.c b/error.c
index 4a4565e7b1..e3348dc7b5 100644
--- a/error.c
+++ b/error.c
@@ -420,7 +420,7 @@ rb_check_type(VALUE x, int t)
 	    if (type->type == t) {
 		const char *etype;
 
-		etype = builtin_type_name(xt);
+		etype = builtin_type_name(x);
 		rb_raise(rb_eTypeError, "wrong argument type %s (expected %s)",
 			 etype, type->name);
 	    }