diff --git a/ChangeLog b/ChangeLog
index ae0bdc8169..2a44dfd936 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Thu Dec  2 01:24:39 2010  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* ext/json/lib/json/common.rb: don't use iconv on 1.9.
+	  patched by Shota Fukumori [ruby-core:33164]
+
 Thu Dec  2 01:02:03 2010  NARUSE, Yui  <naruse@ruby-lang.org>
 
 	* ext/json: Update github/flori/json from 1.4.2+ to
diff --git a/ext/json/lib/json/common.rb b/ext/json/lib/json/common.rb
index d5444b92c8..13debd1366 100644
--- a/ext/json/lib/json/common.rb
+++ b/ext/json/lib/json/common.rb
@@ -1,5 +1,4 @@
 require 'json/version'
-require 'iconv'
 
 module JSON
   class << self
@@ -342,8 +341,15 @@ module JSON
   end
 
   # Shortuct for iconv.
-  def self.iconv(to, from, string)
-    Iconv.iconv(to, from, string).first
+  if String.method_defined?(:encode)
+    def self.iconv(to, from, string)
+      string.encode(to, from)
+    end
+  else
+    require 'iconv'
+    def self.iconv(to, from, string)
+      Iconv.iconv(to, from, string).first
+    end
   end
 end
 
diff --git a/test/json/test_json_encoding.rb b/test/json/test_json_encoding.rb
index fdea329605..cdeca58092 100644
--- a/test/json/test_json_encoding.rb
+++ b/test/json/test_json_encoding.rb
@@ -7,7 +7,6 @@ when 'pure' then require 'json/pure'
 when 'ext'  then require 'json/ext'
 else             require 'json'
 end
-require 'iconv'
 
 class TC_JSONEncoding < Test::Unit::TestCase
   include JSON
@@ -15,19 +14,21 @@ class TC_JSONEncoding < Test::Unit::TestCase
   def setup
     @utf_8 = '["© ≠ €!"]'
     @parsed = [ "© ≠ €!" ]
-    @utf_16_data = Iconv.iconv('utf-16be', 'utf-8', @parsed.first)
     @generated = '["\u00a9 \u2260 \u20ac!"]'
-    if defined?(::Encoding)
+    if String.method_defined?(:encode)
+      @utf_16_data = [@parsed.first.encode('utf-16be', 'utf-8')]
       @utf_8_ascii_8bit = @utf_8.dup.force_encoding(Encoding::ASCII_8BIT)
-      @utf_16be, = Iconv.iconv('utf-16be', 'utf-8', @utf_8)
+      @utf_16be = @utf_8.encode('utf-16be', 'utf-8')
       @utf_16be_ascii_8bit = @utf_16be.dup.force_encoding(Encoding::ASCII_8BIT)
-      @utf_16le, = Iconv.iconv('utf-16le', 'utf-8', @utf_8)
+      @utf_16le = @utf_8.encode('utf-16le', 'utf-8')
       @utf_16le_ascii_8bit = @utf_16le.dup.force_encoding(Encoding::ASCII_8BIT)
-      @utf_32be, = Iconv.iconv('utf-32be', 'utf-8', @utf_8)
+      @utf_32be = @utf_8.encode('utf-32be', 'utf-8')
       @utf_32be_ascii_8bit = @utf_32be.dup.force_encoding(Encoding::ASCII_8BIT)
-      @utf_32le, = Iconv.iconv('utf-32le', 'utf-8', @utf_8)
+      @utf_32le = @utf_8.encode('utf-32le', 'utf-8')
       @utf_32le_ascii_8bit = @utf_32le.dup.force_encoding(Encoding::ASCII_8BIT)
     else
+      require 'iconv'
+      @utf_16_data = Iconv.iconv('utf-16be', 'utf-8', @parsed.first)
       @utf_8_ascii_8bit = @utf_8.dup
       @utf_16be, = Iconv.iconv('utf-16be', 'utf-8', @utf_8)
       @utf_16be_ascii_8bit = @utf_16be.dup