The first report of external supravesical hernia was made by Astley Cooper in 1804, but it is so rare that we could not find any case reported in Japan. Here we report a case of external supravesical hernia in a male who had bladder cancer. This hernia was reported to be caused by fragility induced by operation or radiotherapy. It can be confused with inguinal direct hernia because it is not considered in the differential diagnosis. Findings such as a palpable hernia sack and the orifice can enable correct diagnosis. Surgical treatment is the only treatment of choice for this disorder.