diff --git a/lib/chainer/iterators/serial_iterator.rb b/lib/chainer/iterators/serial_iterator.rb
index f9c97ab..477e950 100644
--- a/lib/chainer/iterators/serial_iterator.rb
+++ b/lib/chainer/iterators/serial_iterator.rb
@@ -33,9 +33,8 @@ def next
               else
                 batch = @dataset[0...rest].map { |index| @dataset[index] }
               end
-
-              @current_position = rest
             end
+            @current_position = rest
           else
             @current_position = 0
           end