diff --git a/ChangeLog b/ChangeLog
index d6150a7eaa..a0735681ef 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Apr 23 11:49:54 2008  Akinori MUSHA  <knu@iDaemons.org>
+
+	* lib/set.rb (Set#each, SortedSet#each, TC_Set#test_each): Return
+	  an enumerator if no block is given.
+
 Wed Apr 23 00:36:03 2008  Yusuke Endoh  <mame@tsg.ne.jp>
 
 	* test/openssl/test_ssl.rb (start_server): add timeout to server.join.
diff --git a/lib/set.rb b/lib/set.rb
index 3b30db0537..b925f8e586 100644
--- a/lib/set.rb
+++ b/lib/set.rb
@@ -2,7 +2,7 @@
 #--
 # set.rb - defines the Set class
 #++
-# Copyright (c) 2002 Akinori MUSHA <knu@iDaemons.org>
+# Copyright (c) 2002-2008 Akinori MUSHA <knu@iDaemons.org>
 #
 # Documentation by Akinori MUSHA and Gavin Sinclair. 
 #
@@ -204,8 +204,10 @@ class Set
   end
 
   # Calls the given block once for each element in the set, passing
-  # the element as parameter.
+  # the element as parameter.  Returns an enumerator if no block is
+  # given.
   def each
+    block_given? or return enum_for(__method__)
     @hash.each_key { |o| yield(o) }
     self
   end
@@ -511,6 +513,7 @@ class SortedSet < Set
 	  end
 
 	  def each
+	    block_given? or return enum_for(__method__)
 	    to_a.each { |o| yield(o) }
 	  end
 
@@ -925,9 +928,8 @@ class TC_Set < Test::Unit::TestCase
     ary = [1,3,5,7,10,20]
     set = Set.new(ary)
 
-    assert_raises(LocalJumpError) {
-      set.each
-    }
+    e = set.each
+    assert_instance_of(Enumerable::Enumerator, e)
 
     assert_nothing_raised {
       set.each { |o|