Here we report a rare case of inflammatory myofibroblastic tumor of the bladder. The patient was a 72-year-old man. We diagnosed this case preoperatively as urachal tumor from urine cytology, cystoscopy, and magnetic resonance imaging. We performed partial cystectomy. Histopathological examination revealed that the tumor was an inflammatory myofibroblastic tumor. To our knowledge, this is the 51st reported case of inflammatory myofibroblastic tumor of the bladder in Japan. He has been followed up for 13 months without any evidence of local recurrence.