diff --git a/ChangeLog b/ChangeLog
index ad8363ecb1..8bd5332a9b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,4 +1,7 @@
-Mon Jun 13 23:28:50 2011  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+Mon Jun 13 23:33:31 2011  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* ext/io/console/console.c (console_dev): console should be
+	  unbuffered.
 
 	* ext/io/console/console.c (console_dev): take care of no-ctty
 	  case.
diff --git a/ext/io/console/console.c b/ext/io/console/console.c
index c2660d2ac9..635c2afc9b 100644
--- a/ext/io/console/console.c
+++ b/ext/io/console/console.c
@@ -587,7 +587,9 @@ console_dev(VALUE klass)
 	fptr->f2 = ofptr->f;
 	ofptr->f = 0;
 # endif
+	optr->mode |= FMODE_SYNC;
 #endif
+	fptr->mode |= FMODE_SYNC;
 	rb_const_set(klass, id_console, con);
     }
     return con;
diff --git a/test/io/console/test_io_console.rb b/test/io/console/test_io_console.rb
index 5475a93fa3..b06b5d5c67 100644
--- a/test/io/console/test_io_console.rb
+++ b/test/io/console/test_io_console.rb
@@ -148,6 +148,10 @@ class TestIO_Console < Test::Unit::TestCase
     }
   end
 
+  def test_sync
+    assert(helper {IO.console.sync}, "console should be unbuffered")
+  end
+
   private
   def helper
     m, s = PTY.open