diff --git a/ChangeLog b/ChangeLog
index 420fe6b2d9..5934958e9e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Mon Dec  3 15:50:33 2012  Akinori MUSHA  <knu@iDaemons.org>
+
+	* misc/ruby-additional.el (ruby-mode-set-encoding): Unbreak by
+	  fixing a typo, s/set/setq/.
+
 Mon Dec 03 14:14:19 2012  Koichi Sasada  <ko1@atdot.net>
 
 	* compile.c (iseq_compile_each): joke shouldn't use id.h defined ids.
diff --git a/misc/ruby-additional.el b/misc/ruby-additional.el
index 32811728e3..152067e48e 100644
--- a/misc/ruby-additional.el
+++ b/misc/ruby-additional.el
@@ -67,9 +67,9 @@ Now encoding needs to be set always explicitly actually."
 	  (if (re-search-forward "[^\0-\177]" nil t)
 	      (progn
 		(goto-char (point-min))
-		(set coding-system
-		     (or coding-system-for-write
-			 buffer-file-coding-system))
+		(setq coding-system
+                      (or coding-system-for-write
+                          buffer-file-coding-system))
 		(if coding-system
 		    (setq coding-system
 			  (or (coding-system-get coding-system 'mime-charset)