diff --git a/src/Makefile.am b/src/Makefile.am
index a5e2aefc..b4e64306 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -482,7 +482,7 @@ SRCS += Metalinker.cc Metalinker.h\
 	MetalinkParserStateV4Impl.cc MetalinkParserStateV4Impl.h\
 	Metalink2RequestGroup.cc Metalink2RequestGroup.h\
 	MetalinkPostDownloadHandler.cc MetalinkPostDownloadHandler.h\
-	MetalinkHelper.cc MetalinkHelper.h
+	metalink_helper.cc metalink_helper.h
 endif # ENABLE_METALINK
 
 if ENABLE_METALINK_LIBXML2
diff --git a/src/Metalink2RequestGroup.cc b/src/Metalink2RequestGroup.cc
index c020d7ac..c8c4ce03 100644
--- a/src/Metalink2RequestGroup.cc
+++ b/src/Metalink2RequestGroup.cc
@@ -44,7 +44,7 @@
 #include "util.h"
 #include "message.h"
 #include "DownloadContext.h"
-#include "MetalinkHelper.h"
+#include "metalink_helper.h"
 #include "BinaryStream.h"
 #include "MemoryBufferPreDownloadHandler.h"
 #include "TrueRequestGroupCriteria.h"
@@ -113,7 +113,7 @@ Metalink2RequestGroup::generate
  const SharedHandle<Option>& option)
 {
   std::vector<SharedHandle<MetalinkEntry> > entries;
-  MetalinkHelper::parseAndQuery(entries, metalinkFile, option.get());
+  metalink::parseAndQuery(entries, metalinkFile, option.get());
   std::vector<SharedHandle<RequestGroup> > tempgroups;
   createRequestGroup(tempgroups, entries, option);
   SharedHandle<MetadataInfo> mi;
@@ -133,7 +133,7 @@ Metalink2RequestGroup::generate
  const SharedHandle<Option>& option)
 {
   std::vector<SharedHandle<MetalinkEntry> > entries;
-  MetalinkHelper::parseAndQuery(entries, binaryStream, option.get());
+  metalink::parseAndQuery(entries, binaryStream, option.get());
   std::vector<SharedHandle<RequestGroup> > tempgroups;
   createRequestGroup(tempgroups, entries, option);
   SharedHandle<MetadataInfo> mi(new MetadataInfo());
@@ -191,7 +191,7 @@ Metalink2RequestGroup::createRequestGroup
                 mem_fun_sh(&MetalinkEntry::reorderMetaurlsByPriority));
   std::vector<std::pair<std::string,
     std::vector<SharedHandle<MetalinkEntry> > > > entryGroups;
-  MetalinkHelper::groupEntryByMetaurlName(entryGroups, selectedEntries);
+  metalink::groupEntryByMetaurlName(entryGroups, selectedEntries);
   for(std::vector<std::pair<std::string,
         std::vector<SharedHandle<MetalinkEntry> > > >::const_iterator itr =
         entryGroups.begin(), eoi = entryGroups.end(); itr != eoi; ++itr) {
diff --git a/src/main.cc b/src/main.cc
index 62cd25c2..3ce79c79 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -73,7 +73,7 @@
 # include "bittorrent_helper.h"
 #endif // ENABLE_BITTORRENT
 #ifdef ENABLE_METALINK
-# include "MetalinkHelper.h"
+# include "metalink_helper.h"
 # include "MetalinkEntry.h"
 #endif // ENABLE_METALINK
 #ifdef ENABLE_MESSAGE_DIGEST
@@ -127,7 +127,7 @@ void showMetalinkFile
 (const std::string& uri, const SharedHandle<Option>& op)
 {
   std::vector<SharedHandle<MetalinkEntry> > metalinkEntries;
-  MetalinkHelper::parseAndQuery(metalinkEntries, uri, op.get());
+  metalink::parseAndQuery(metalinkEntries, uri, op.get());
   std::vector<SharedHandle<FileEntry> > fileEntries;
   MetalinkEntry::toFileEntry(fileEntries, metalinkEntries);
   util::toStream(fileEntries.begin(), fileEntries.end(), std::cout);
diff --git a/src/MetalinkHelper.cc b/src/metalink_helper.cc
similarity index 87%
rename from src/MetalinkHelper.cc
rename to src/metalink_helper.cc
index a90a65ee..8a367ff6 100644
--- a/src/MetalinkHelper.cc
+++ b/src/metalink_helper.cc
@@ -32,7 +32,7 @@
  * files in the program, then also delete it here.
  */
 /* copyright --> */
-#include "MetalinkHelper.h"
+#include "metalink_helper.h"
 #include "Option.h"
 #include "MetalinkEntry.h"
 #include "MetalinkParserStateMachine.h"
@@ -45,31 +45,14 @@
 
 namespace aria2 {
 
-MetalinkHelper::MetalinkHelper() {}
+namespace metalink {
 
-MetalinkHelper::~MetalinkHelper() {}
+namespace {
 
-void MetalinkHelper::parseAndQuery
+void query
 (std::vector<SharedHandle<MetalinkEntry> >& result,
- const std::string& filename, const Option* option)
-{
-  MetalinkProcessor proc;
-  SharedHandle<Metalinker> metalinker = proc.parseFile(filename);
-  query(result, metalinker, option);
-}
-
-void MetalinkHelper::parseAndQuery
-(std::vector<SharedHandle<MetalinkEntry> >& result,
- const SharedHandle<BinaryStream>& binaryStream, const Option* option)
-{
-  MetalinkProcessor proc;
-  SharedHandle<Metalinker> metalinker =proc.parseFromBinaryStream(binaryStream);
-  query(result, metalinker, option);
-}
-
-void MetalinkHelper::query
-(std::vector<SharedHandle<MetalinkEntry> >& result,
- const SharedHandle<Metalinker>& metalinker, const Option* option)
+ const SharedHandle<Metalinker>& metalinker,
+ const Option* option)
 {
   metalinker->queryEntry(result,
                          option->get(PREF_METALINK_VERSION),
@@ -77,9 +60,31 @@ void MetalinkHelper::query
                          option->get(PREF_METALINK_OS));
 }
 
-void MetalinkHelper::groupEntryByMetaurlName
+} // namespace
+
+void parseAndQuery
+(std::vector<SharedHandle<MetalinkEntry> >& result,
+ const std::string& filename,
+ const Option* option)
+{
+  MetalinkProcessor proc;
+  SharedHandle<Metalinker> metalinker = proc.parseFile(filename);
+  query(result, metalinker, option);
+}
+
+void parseAndQuery
+(std::vector<SharedHandle<MetalinkEntry> >& result,
+ const SharedHandle<BinaryStream>& binaryStream,
+ const Option* option)
+{
+  MetalinkProcessor proc;
+  SharedHandle<Metalinker> metalinker =proc.parseFromBinaryStream(binaryStream);
+  query(result, metalinker, option);
+}
+
+void groupEntryByMetaurlName
 (std::vector<
- std::pair<std::string, std::vector<SharedHandle<MetalinkEntry> > > >& result,
+  std::pair<std::string, std::vector<SharedHandle<MetalinkEntry> > > >& result,
  const std::vector<SharedHandle<MetalinkEntry> >& entries)
 {
   for(std::vector<SharedHandle<MetalinkEntry> >::const_iterator eiter =
@@ -114,4 +119,6 @@ void MetalinkHelper::groupEntryByMetaurlName
   }
 }
 
+} // namespace metalink
+
 } // namespace aria2
diff --git a/src/MetalinkHelper.h b/src/metalink_helper.h
similarity index 72%
rename from src/MetalinkHelper.h
rename to src/metalink_helper.h
index 08b446e0..3728c4a1 100644
--- a/src/MetalinkHelper.h
+++ b/src/metalink_helper.h
@@ -49,30 +49,24 @@ class MetalinkEntry;
 class BinaryStream;
 class Metalinker;
 
-class MetalinkHelper {
-private:
-  MetalinkHelper();
+namespace metalink {
 
-  ~MetalinkHelper();
+void parseAndQuery
+(std::vector<SharedHandle<MetalinkEntry> >& result,
+ const std::string& filename,
+ const Option* option);
 
-  static void query
-  (std::vector<SharedHandle<MetalinkEntry> >& result,
-   const SharedHandle<Metalinker>& metalinker, const Option* option);
+void parseAndQuery
+(std::vector<SharedHandle<MetalinkEntry> >& result,
+ const SharedHandle<BinaryStream>& binaryStream,
+ const Option* option);
 
-public:
-  static void parseAndQuery
-  (std::vector<SharedHandle<MetalinkEntry> >& result,
-   const std::string& filename, const Option* option);
+void groupEntryByMetaurlName
+(std::vector<
+  std::pair<std::string, std::vector<SharedHandle<MetalinkEntry> > > >& result,
+ const std::vector<SharedHandle<MetalinkEntry> >& entries);
 
-  static void parseAndQuery
-  (std::vector<SharedHandle<MetalinkEntry> >& result,
-   const SharedHandle<BinaryStream>& binaryStream, const Option* option);
-
-  static void groupEntryByMetaurlName
-  (std::vector<
-   std::pair<std::string, std::vector<SharedHandle<MetalinkEntry> > > >& result,
-   const std::vector<SharedHandle<MetalinkEntry> >& entries);
-};
+} // namespace metalink
 
 } // namespace aria2
 
diff --git a/test/MetalinkHelperTest.cc b/test/MetalinkHelperTest.cc
index cb404fe2..a186c392 100644
--- a/test/MetalinkHelperTest.cc
+++ b/test/MetalinkHelperTest.cc
@@ -1,4 +1,4 @@
-#include "MetalinkHelper.h"
+#include "metalink_helper.h"
 
 #include <cppunit/extensions/HelperMacros.h>
 
@@ -31,7 +31,7 @@ void MetalinkHelperTest::testParseAndQuery()
 {
   Option option;
   std::vector<SharedHandle<MetalinkEntry> > result;
-  MetalinkHelper::parseAndQuery(result, A2_TEST_DIR"/test.xml", &option);
+  metalink::parseAndQuery(result, A2_TEST_DIR"/test.xml", &option);
   CPPUNIT_ASSERT_EQUAL((size_t)5, result.size());
 }
 
@@ -40,7 +40,7 @@ void MetalinkHelperTest::testParseAndQuery_version()
   Option option;
   option.put(PREF_METALINK_VERSION, "0.5.1");
   std::vector<SharedHandle<MetalinkEntry> > result;
-  MetalinkHelper::parseAndQuery(result, A2_TEST_DIR"/test.xml", &option);
+  metalink::parseAndQuery(result, A2_TEST_DIR"/test.xml", &option);
   CPPUNIT_ASSERT_EQUAL((size_t)1, result.size());
   SharedHandle<MetalinkEntry> entry = result.front();
   CPPUNIT_ASSERT_EQUAL(std::string("aria2-0.5.1.tar.bz2"), entry->getPath());
@@ -99,7 +99,7 @@ void MetalinkHelperTest::testGroupEntryByMetaurlName()
 
   std::vector<std::pair<std::string,
     std::vector<SharedHandle<MetalinkEntry> > > > result;
-  MetalinkHelper::groupEntryByMetaurlName(result, entries);
+  metalink::groupEntryByMetaurlName(result, entries);
 
   CPPUNIT_ASSERT_EQUAL(std::string("http://meta1"), result[0].first);
   CPPUNIT_ASSERT_EQUAL(std::string("1"), result[0].second[0]->version);