diff --git a/ChangeLog b/ChangeLog
index cdf77e6c83..2296b34f54 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,7 +1,7 @@
-Tue Nov 15 01:03:32 2011  Ayumu AIZAWA  <ayumu.aizawa@gmail.com>
+Tue Nov 15 01:53:48 2011  Ayumu AIZAWA  <ayumu.aizawa@gmail.com>
 
 	* test/ruby/test_io.rb (test_fcntl_dupfd): fix test error on
-	  SnowLeopard.
+	  SnowLeopard. Pointed out by CHIKANAGA Tomoyuki. [ruby-dev:44866]
 
 Mon Nov 14 22:06:02 2011  Tanaka Akira  <akr@fsij.org>
 
diff --git a/test/ruby/test_io.rb b/test/ruby/test_io.rb
index e1ec389dc4..7256e6fc16 100644
--- a/test/ruby/test_io.rb
+++ b/test/ruby/test_io.rb
@@ -1919,11 +1919,10 @@ End
   end
 
   def test_fcntl_dupfd
-    Tempfile.new(self.class.name) do |f|
-      f.open
-      fd = f.fcntl(Fcntl::F_DUPFD, 500)
+    Tempfile.open(self.class.name) do |f|
+      fd = f.fcntl(Fcntl::F_DUPFD, 255)
       begin
-        assert_equal(fd, 500)
+        assert_equal(fd, 255)
       ensure
         IO.for_fd(fd).close
       end