diff --git a/ChangeLog b/ChangeLog
index f024a1a748..f86109ce59 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Jun 24 11:41:20 2009  Akinori MUSHA  <knu@iDaemons.org>
+
+	* misc/ruby-style.el: It is too late to set c-file-style in
+	  c-mode-hook (at least on Emacs 23).  Call c-set-style instead.
+
 Tue Jun 23 21:28:16 2009  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* file.c (rb_get_path_check): check with given safe level.
diff --git a/misc/ruby-style.el b/misc/ruby-style.el
index 0fe4a83089..6dc444273c 100644
--- a/misc/ruby-style.el
+++ b/misc/ruby-style.el
@@ -7,14 +7,15 @@
 ;;;  $Author$
 ;;;  created at: Thu Apr 26 13:54:01 JST 2007
 ;;;
-;;; sets ruby style if it seems like a source of ruby.
+;;; To switch to the "ruby" style automatically if it looks like a
+;;; source file of ruby, add ruby-style-c-mode to c-mode-hook:
 ;;;
 ;;;   (require 'ruby-style)
 ;;;   (add-hook 'c-mode-hook 'ruby-style-c-mode)
 ;;;   (add-hook 'c++-mode-hook 'ruby-style-c-mode)
 ;;;
-;;; uses ruby style always.
-;;;   (setq-default c-file-style "ruby")
+;;; Customize the c-default-style variable to set the default style
+;;; for each CC major mode.
 
 (defconst ruby-style-revision "$Revision$"
   "Ruby style revision string.")
@@ -71,6 +72,6 @@
                   (case-fold-search nil))
               (goto-char (point-min))
               (re-search-forward "Copyright (C) .* Yukihiro Matsumoto" head t))))
-      (setq c-file-style "ruby")))
+      (c-set-style "ruby")))
 
 (provide 'ruby-style)