Abstract The home advantage has been popular phenomenon in sport. However, very little systematic research has been carried out in Japan. The purpose of the present paper is to provide an empirical evidence of the home advantage in the Nippon Professional Baseball （NPB）. The results revealed that home winning percentage in the NPB was 55.3%. There were no differences in degree of home advantage between the NPB and the Major League Baseball （MLB）. We discussed four factors thought to be responsible for home advantage.
