diff --git a/ChangeLog b/ChangeLog
index c9a3ca78c9..ccd728c1db 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Apr 14 12:56:21 2010  Shugo Maeda  <shugo@ruby-lang.org>
+
+	* lib/net/imap (encode_utf7): encode & properly.  Thanks, Kengo
+	  Matsuyama.  [ruby-dev:38063]
+
 Wed Apr 14 11:39:26 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* ext/syck/lib/syck/basenode.rb (Syck::BaseNode#match_path): fixed
diff --git a/lib/net/imap.rb b/lib/net/imap.rb
index 980fed61ca..6f1a578144 100644
--- a/lib/net/imap.rb
+++ b/lib/net/imap.rb
@@ -911,7 +911,7 @@ module Net
 
     # Encode a string from UTF-8 format to modified UTF-7.
     def self.encode_utf7(s)
-      return s.gsub(/(&)|([^\x20-\x25\x27-\x7e]+)/u) {
+      return s.gsub(/(&)|([^\x20-\x7e]+)/u) {
         if $1
           "&-"
         else
diff --git a/test/net/imap/test_imap.rb b/test/net/imap/test_imap.rb
index b7714dff1a..501298cdc4 100644
--- a/test/net/imap/test_imap.rb
+++ b/test/net/imap/test_imap.rb
@@ -19,6 +19,10 @@ class IMAPTest < Test::Unit::TestCase
     utf8 = "\357\274\241\357\274\242\357\274\243".force_encoding("UTF-8")
     s = Net::IMAP.encode_utf7(utf8)
     assert_equal("&,yH,Iv8j-".force_encoding("UTF-8"), s)
+
+    utf8 = "\343\201\202&".force_encoding("UTF-8")
+    s = Net::IMAP.encode_utf7(utf8)
+    assert_equal("&MEI-&-".force_encoding("UTF-8"), s)
   end
 
   def test_decode_utf7