diff --git a/ChangeLog b/ChangeLog
index 7e10c8c1..2c706c0c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2010-11-25  Tatsuhiro Tsujikawa  <t-tujikawa@users.sourceforge.net>
+
+	Removed MultiDiskAdaptor::mkdir() because directory structure is
+	created at AbstractDiskWriter::createFile().
+	* src/MultiDiskAdaptor.cc
+	* src/MultiDiskAdaptor.h
+
 2010-11-25  Tatsuhiro Tsujikawa  <t-tujikawa@users.sourceforge.net>
 
 	Fixed unittest error
diff --git a/src/MultiDiskAdaptor.cc b/src/MultiDiskAdaptor.cc
index 18586088..0c37c0df 100644
--- a/src/MultiDiskAdaptor.cc
+++ b/src/MultiDiskAdaptor.cc
@@ -263,15 +263,6 @@ void MultiDiskAdaptor::resetDiskWriterEntries()
   }
 }
 
-void MultiDiskAdaptor::mkdir() const
-{
-  for(std::vector<SharedHandle<DiskWriterEntry> >::const_iterator i =
-        diskWriterEntries_.begin(), eoi = diskWriterEntries_.end();
-      i != eoi; ++i) {
-    (*i)->getFileEntry()->setupDir();
-  }
-}
-
 void MultiDiskAdaptor::openIfNot
 (const SharedHandle<DiskWriterEntry>& entry, void (DiskWriterEntry::*open)())
 {
@@ -303,7 +294,9 @@ void MultiDiskAdaptor::openIfNot
 void MultiDiskAdaptor::openFile()
 {
   resetDiskWriterEntries();
-  mkdir();
+  // util::mkdir() is called in AbstractDiskWriter::createFile(), so
+  // we don't need to call it here.
+
   // Call DiskWriterEntry::openFile to make sure that zero-length files are
   // created.
   for(DiskWriterEntries::const_iterator itr = diskWriterEntries_.begin(),
@@ -315,7 +308,9 @@ void MultiDiskAdaptor::openFile()
 void MultiDiskAdaptor::initAndOpenFile()
 {
   resetDiskWriterEntries();
-  mkdir();
+  // util::mkdir() is called in AbstractDiskWriter::createFile(), so
+  // we don't need to call it here.
+
   // Call DiskWriterEntry::initAndOpenFile to make files truncated.
   for(DiskWriterEntries::const_iterator itr = diskWriterEntries_.begin(),
         eoi = diskWriterEntries_.end(); itr != eoi; ++itr) {
diff --git a/src/MultiDiskAdaptor.h b/src/MultiDiskAdaptor.h
index 6be2f634..901f72c0 100644
--- a/src/MultiDiskAdaptor.h
+++ b/src/MultiDiskAdaptor.h
@@ -128,8 +128,6 @@ private:
 
   void resetDiskWriterEntries();
 
-  void mkdir() const;
-
   void openIfNot(const SharedHandle<DiskWriterEntry>& entry,
                  void (DiskWriterEntry::*f)());