We herein report a rare case of leiomyoma in the retroperitoneal space posterior to the urinary bladder. A 61-year-old man came to our department complaining of lower abdominal discomfort. Abdominal and pelvic computed tomographic scan revealed a retrovesical solid tumor on the cranial side to the left seminal vesicle. Diagnostic imaging suggested that the retrovesical tumor was a benign tumor such as leiomyoma or fibroma, and he underwent simple resection of this retrovesical tumor via reroperitoneal approach. Histopathological diagnosis was well compatible with image diagnosis of leiomyoma. He has been followed up for 6 months without recurrence.