Old people are prone to get weak in their physical bodies as well as their memorizations. We have developed a serious game for the elderly named 'Paldokangsan 3' which is a walking game strengthening the ability of memorization with the interface of motion capture using Kinect. The expected effects are improvement of memorization, concentration and vitality through the game. We showed their improvements with a confidence of 99% by the experiments with 25 old people of more than 65 year old.