diff --git a/ChangeLog b/ChangeLog
index 29cf0c5716..850daf3d5d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Tue Oct 12 17:53:49 2010  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* numeric (check_uint): the mask must refer to VALUE.
+
 Tue Oct 12 17:47:10 2010  NARUSE, Yui  <naruse@ruby-lang.org>
 
 	* numeric (check_uint): set MSB for negative value.
diff --git a/numeric.c b/numeric.c
index 9b01acfd10..65d501ae1e 100644
--- a/numeric.c
+++ b/numeric.c
@@ -1791,8 +1791,8 @@ check_uint(VALUE num, VALUE sign)
     if (RTEST(sign)) {
 	/* minus */
 	if ((num & mask) != mask || (num & ~mask) <= INT_MAX + 1UL)
-#define MSBMASK   (1L << ((sizeof(long) * CHAR_BIT) - 1))
-	    rb_raise(rb_eRangeError, "integer %"PRIdVALUE " too small to convert to `unsigned int'", num|MSBMASK);
+#define VALUE_MSBMASK   (1L << ((sizeof(VALUE) * CHAR_BIT) - 1))
+	    rb_raise(rb_eRangeError, "integer %"PRIdVALUE " too small to convert to `unsigned int'", num|VALUE_MSBMASK);
     }
     else {
 	/* plus */