The foraging strategy of Japanese black bears could be either the “energy maximizer” which increases their fitness by maximizing their energy intake, or the “time minimizer” which increases their fitness by minimizing foraging time by eating fixed amount of foods to spend more time for other activities(e.g., mating). We examined the foraging strategy of bears in summer and autumn using captive bears. We fed 3 bears ad libitum and fed 3 bears less than their estimated basal metabolic rate (BMR) for 10 days. We fed Actinidia deliciosafruits and Quercus crispula acorns in summer and autumn, respectively. Then their time budgets for foraging, amount of food intake and body weight at the beginning and the end of the experiment were measured.We found that there were no large differences in foraging time between the two experimental methods in summer. The body weights of bears which were fed ad libitum decreased after the experiment in summer. On the other hand, foraging time of the bears which were fed ad libitum were 3 to 4 times longer than the bears which were fed less than their BMR in autumn. Their energy intake was 1 to 2 times more than their BMR. The results suggest that the Japanese black bears took the time minimizer strategy in summer and the energy maximizer strategy in autumn.