diff --git a/ChangeLog b/ChangeLog
index 68343d3c70..1db6c476d8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sat Nov  3 14:43:42 2012  Kouhei Sutou  <kou@cozmixng.org>
+
+	* lib/rexml/xmldecl.rb (REXML::XMLDecl#content): Add missing \A
+	  and \z.
+
 Sat Nov  3 14:42:55 2012  Kouhei Sutou  <kou@cozmixng.org>
 
 	* lib/rexml/output.rb (REXML::Output#initialize): Use normalized
diff --git a/lib/rexml/xmldecl.rb b/lib/rexml/xmldecl.rb
index eac4b17971..465e6abeb7 100644
--- a/lib/rexml/xmldecl.rb
+++ b/lib/rexml/xmldecl.rb
@@ -107,7 +107,7 @@ module REXML
     private
     def content(enc)
       rv = "version='#@version'"
-      rv << " encoding='#{enc}'" if @writeencoding || enc !~ /utf-8/i
+      rv << " encoding='#{enc}'" if @writeencoding || enc !~ /\Autf-8\z/i
       rv << " standalone='#@standalone'" if @standalone
       rv
     end