We studied the relationships between movement and foraging habits of the Asiatic black bear (Ursus thibetanus) and hard mast production of five tree species in cool temperate forest during 2006–2008. The purpose of this study was to test the hypothesis that low mast production affects sexual differences in bear behavior. We summarized the movement pattern of 13 bears in terms of minimum movement distance and cumulative movement distance of the movement path followed during 24 hour. Masting of Quercus crispula acorns was low in 2006, high in 2007 and moderate in 2008. The dominant food items found in bear scats were hard mast, especially Quercus acorns. The percentage of Quercus acorns in the food items in scats was higher in 2007 than in 2006 and 2008. Movement distance of males and females increased in the low mast year. However, the increase of movement distance of females was larger than that of males. Thus, masting influenced the behavior of females more strongly than males. Our results indicated that low mast production changed the food habits and the size of the home range of bears, especially of females.