Seed production of Fagaceae species in autumn changes substantially and synchronously from year to year, and Asian black bears eat mainly this hard mast to accumulate fat for hibernation. We explored the impacts of masting on bear reproductive success from width of the annuli formed in tooth cementum as index of cub survival. We hypothesized that more female bears would successfully give birth and raise cubs in years following good mast years. In poor mast years, most bears would not reproduce, whereas in years following good mast years, although some females would not reproduce, more bears could reproduce. We also hypothesized that cementum annulus width among individuals would vary greatly in years following good mast years. We used 53 adult female teeth to calculate the proportional width index (PWI) of the annuli and data of beech seed production from 1989 to 2015 in northeastern Japan. We estimated the effects of masting on PWI of following year by linear mixed model and generalized linear model. There was no relationship between masting and PWI. We concluded that masting of dominant hard mast species has no impact on bear reproductive success, because bears can exploit various foods and other factors may affect reproduction.