We investigated the effect of boiling on the anthocyanin content and the antioxidative activity of Shogatsu-mame beans in compariosn with black soybeans. The anthocyanin content of Shogatsu-mame beans was significantly lower than that of black soybeans. The boiling procedure led to a reduction in the anthocyanin content of boiled Shogatsu-mame beans to 11.3%, while a much greater reduction was apparent with black soybeans, and only 4.9% of anthocyanin remained, probably due to a longer boiling time. The antioxidative activity of raw Shogatsu-mame beans was significantly lower than that of raw black soybeans. However, after boiling Shogatsu-mame beans, the antioxidative activity had decreased to 63.2%, while that of black soybeans had decreased to 54.3%. As the result, no significant difference in the antioxidative activity after boiling was observed between boiled Shogatsu-mame beans and black soybeans.