diff --git a/ChangeLog b/ChangeLog
index 80ae14e802..a1a5f4fde3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+Sat Nov  3 12:49:45 2012  Kouhei Sutou  <kou@cozmixng.org>
+
+	* lib/rexml/document.rb (REXML::Document#write): Document encoding
+	  option. Now different encoding between XML file's encoding and
+	  XML declaration's encodiong is support.
+	  [Feature #4872] (work in progress)
+	* lib/rexml/xmldecl.rb (REXML::XMLDecl#write): Always use XMLDecl's
+	  encoding.
+	* test/rexml/test_document.rb: Update tests for the above change.
+
 Sat Nov  3 12:36:35 2012  Kouhei Sutou  <kou@cozmixng.org>
 
 	* lib/rexml/xmldecl.rb (REXML::XMLDecl): Stop using REXML::Encoding
diff --git a/lib/rexml/document.rb b/lib/rexml/document.rb
index 5508a60be4..f9fdbdaab3 100644
--- a/lib/rexml/document.rb
+++ b/lib/rexml/document.rb
@@ -145,8 +145,8 @@ module REXML
     end
 
     # :call-seq:
-    #    doc.write(output=$stdout, indent=-1, transtive=false, ie_hack=false)
-    #    doc.write(options={:output => $stdout, :indent => -1, :transtive => false, :ie_hack => false})
+    #    doc.write(output=$stdout, indent=-1, transtive=false, ie_hack=false, encoding=nil)
+    #    doc.write(options={:output => $stdout, :indent => -1, :transtive => false, :ie_hack => false, :encoding => nil})
     #
     # Write the XML tree out, optionally with indent.  This writes out the
     # entire XML document, including XML declarations, doctype declarations,
@@ -199,6 +199,10 @@ module REXML
     #   unable to parse proper XML, we have to provide a hack to generate XML
     #   that IE's limited abilities can handle.  This hack inserts a space
     #   before the /> on empty tags.  Defaults to false
+    # encoding::
+    #   Encoding name as String. Change output encoding to specified encoding
+    #   instead of encoding in XML declaration.
+    #   Defaults to nil. It means encoding in XML declaration is used.
     def write(*arguments)
       if arguments.size == 1 and arguments[0].class == Hash
         options = arguments[0]
diff --git a/lib/rexml/xmldecl.rb b/lib/rexml/xmldecl.rb
index 6b48a6f8ea..783c9233dc 100644
--- a/lib/rexml/xmldecl.rb
+++ b/lib/rexml/xmldecl.rb
@@ -44,11 +44,7 @@ module REXML
     def write(writer, indent=-1, transitive=false, ie_hack=false)
       return nil unless @writethis or writer.kind_of? Output
       writer << START.sub(/\\/u, '')
-      if writer.kind_of? Output
-        writer << " #{content writer.encoding}"
-      else
-        writer << " #{content encoding}"
-      end
+      writer << " #{content encoding}"
       writer << STOP.sub(/\\/u, '')
     end
 
diff --git a/test/rexml/test_document.rb b/test/rexml/test_document.rb
index 2725235907..b78b310f00 100644
--- a/test/rexml/test_document.rb
+++ b/test/rexml/test_document.rb
@@ -165,11 +165,16 @@ EOX
         indent = -1
         transitive = false
         ie_hack = false
-        encoding = "Shift_JIS"
+        encoding = "Windows-31J"
+
+        xml_declaration_encoding = "Shift_JIS"
+        @document.xml_decl.encoding = xml_declaration_encoding
+        japanese_text = "こんにちは"
+        @document.root.text = japanese_text
         @document.write(output, indent, transitive, ie_hack, encoding)
-        assert_equal(<<-EOX, output)
-<?xml version='1.0' encoding='SHIFT_JIS'?>
-<message>Hello world!</message>
+        assert_equal(<<-EOX.encode(encoding), output)
+<?xml version='1.0' encoding='#{xml_declaration_encoding}'?>
+<message>#{japanese_text}</message>
 EOX
       end
     end
@@ -215,10 +220,15 @@ EOX
 
       def test_encoding
         output = ""
-        @document.write(:output => output, :encoding => "Shift_JIS")
-        assert_equal(<<-EOX, output)
-<?xml version='1.0' encoding='SHIFT_JIS'?>
-<message>Hello world!</message>
+        encoding = "Windows-31J"
+        xml_declaration_encoding = "Shift_JIS"
+        @document.xml_decl.encoding = xml_declaration_encoding
+        japanese_text = "こんにちは"
+        @document.root.text = japanese_text
+        @document.write(:output => output, :encoding => encoding)
+        assert_equal(<<-EOX.encode(encoding), output)
+<?xml version='1.0' encoding='#{xml_declaration_encoding}'?>
+<message>#{japanese_text}</message>
 EOX
       end
     end