diff --git a/mrbgems/mruby-hash-ext/mrblib/hash.rb b/mrbgems/mruby-hash-ext/mrblib/hash.rb
index 5775913c3..5f6692b9f 100644
--- a/mrbgems/mruby-hash-ext/mrblib/hash.rb
+++ b/mrbgems/mruby-hash-ext/mrblib/hash.rb
@@ -62,8 +62,8 @@ class Hash
 
   ##
   # call-seq:
-  #     hsh.merge!(other_hash)                                 -> hsh
-  #     hsh.merge!(other_hash){|key, oldval, newval| block}    -> hsh
+  #     hsh.merge!(other_hash..)                                 -> hsh
+  #     hsh.merge!(other_hash..){|key, oldval, newval| block}    -> hsh
   #
   #  Adds the contents of _other_hash_ to _hsh_.  If no block is specified,
   #  entries with duplicate keys are overwritten with the values from
@@ -81,14 +81,19 @@ class Hash
   #                     #=> {"a"=>100, "b"=>200, "c"=>300}
   #
 
-  def merge!(other, &block)
-    raise TypeError, "Hash required (#{other.class} given)" unless Hash === other
-    if block
-      other.each_key{|k|
-        self[k] = (self.has_key?(k))? block.call(k, self[k], other[k]): other[k]
-      }
-    else
-      other.each_key{|k| self[k] = other[k]}
+  def merge!(*others, &block)
+    i = 0; len=others.size
+    while i<len
+      other = others[i]
+      i += 1
+      raise TypeError, "Hash required (#{other.class} given)" unless Hash === other
+      if block
+        other.each_key{|k|
+          self[k] = (self.has_key?(k))? block.call(k, self[k], other[k]): other[k]
+        }
+      else
+        other.each_key{|k| self[k] = other[k]}
+      end
     end
     self
   end
diff --git a/mrbgems/mruby-hash-ext/test/hash.rb b/mrbgems/mruby-hash-ext/test/hash.rb
index 78e8b3a3a..e60eb09b2 100644
--- a/mrbgems/mruby-hash-ext/test/hash.rb
+++ b/mrbgems/mruby-hash-ext/test/hash.rb
@@ -64,6 +64,9 @@ assert('Hash#merge!') do
   assert_raise(TypeError) do
     { 'abc_key' => 'abc_value' }.merge! "a"
   end
+
+  # multiple arguments
+  assert_equal({a:1,b:2,c:3}, {a:1}.merge!({b:2},{c:3}))
 end
 
 assert('Hash#values_at') do