diff --git a/ChangeLog b/ChangeLog
index 1553a0741e..7e5a7f09cd 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Tue Jan 13 11:58:04 2009  Yuki Sonoda (Yugui)  <yugui@yugui.jp>
+
+	* lib/irb/input-method.rb: IRB did not prompt for MSwin32.
+	  [ruby-dev:37686].
+	  Patch by arton <artonx AT yahoo.co.jp>.
+
 Tue Jan 13 12:10:42 2009  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* ext/socket/{getaddrinfo,getnameinfo}.c: need to include ws2tcpip.h
diff --git a/lib/irb/input-method.rb b/lib/irb/input-method.rb
index 407012aa86..0b22d9ca74 100644
--- a/lib/irb/input-method.rb
+++ b/lib/irb/input-method.rb
@@ -45,7 +45,7 @@ module IRB
       @line_no = 0
       @line = []
       @stdin = IO.open(STDIN.to_i, :external_encoding => IRB.conf[:LC_MESSAGES].encoding, :internal_encoding => "-")
-      @stdout = IO.open(STDOUT.to_i, :external_encoding => IRB.conf[:LC_MESSAGES].encoding, :internal_encoding => "-")
+      @stdout = IO.open(STDOUT.to_i, 'w', :external_encoding => IRB.conf[:LC_MESSAGES].encoding, :internal_encoding => "-")
     end
 
     def gets
@@ -106,7 +106,7 @@ module IRB
 	@eof = false
 
 	@stdin = IO.open(STDIN.to_i, :external_encoding => IRB.conf[:LC_MESSAGES].encoding, :internal_encoding => "-")
-	@stdout = IO.open(STDOUT.to_i, :external_encoding => IRB.conf[:LC_MESSAGES].encoding, :internal_encoding => "-")
+	@stdout = IO.open(STDOUT.to_i, 'w', :external_encoding => IRB.conf[:LC_MESSAGES].encoding, :internal_encoding => "-")
       end
 
       def gets