diff --git a/app/models/dmsf_file.rb b/app/models/dmsf_file.rb
index e2d6d0d3..ea969158 100644
--- a/app/models/dmsf_file.rb
+++ b/app/models/dmsf_file.rb
@@ -99,7 +99,7 @@ class DmsfFile < ActiveRecord::Base
   def self.storage_path
     path = Setting.plugin_redmine_dmsf['dmsf_storage_directory']
     if path.blank?
-      path = Pathname.new('files').join('dmsf').to_s
+      path = Pathname.new('files').join('dmsf')
     else
       pn = Pathname.new(path)
       return pn if pn.absolute?
diff --git a/test/unit/dmsf_file_test.rb b/test/unit/dmsf_file_test.rb
index 4a539171..a8958694 100644
--- a/test/unit/dmsf_file_test.rb
+++ b/test/unit/dmsf_file_test.rb
@@ -251,4 +251,26 @@ class DmsfFileTest < RedmineDmsf::Test::UnitTest
     assert_equal 2, csv.size
   end
 
+  def test_storage_path
+    # Backup
+    setting = Setting.plugin_redmine_dmsf['dmsf_storage_directory']
+    # Relative path
+    Setting.plugin_redmine_dmsf['dmsf_storage_directory'] = 'dmsf/files'
+    sp = DmsfFile.storage_path
+    assert_kind_of Pathname, sp
+    assert_equal Rails.root.join(Setting.plugin_redmine_dmsf['dmsf_storage_directory']).to_s, sp.to_s
+    # Empty
+    Setting.plugin_redmine_dmsf['dmsf_storage_directory'] = ''
+    sp = DmsfFile.storage_path
+    assert_kind_of Pathname, sp
+    assert_equal Rails.root.join(Pathname.new('files').join('dmsf')).to_s, sp.to_s
+    # Absolute path
+    Setting.plugin_redmine_dmsf['dmsf_storage_directory'] = '/opt/redmine'
+    sp = DmsfFile.storage_path
+    assert_kind_of Pathname, sp
+    assert_equal '/opt/redmine', sp.to_s
+    # Restore
+    Setting.plugin_redmine_dmsf['dmsf_storage_directory'] = setting
+  end
+
 end
\ No newline at end of file