A 46-year-old man visited our clinic with the chief complaint of indolent swelling of the left scrotal contents. An elastic hard and fist-sized mass with negative transillumination was palpable in left scrotum, but testis and epididymis were not discriminated. Left high orchiectomy was performed. Tumor was 90 X 55 mm in size and the testis and epididymis at the lower pole of the tumor were intact. Histological diagnosis was leiomyoma and we diagnosed leiomyoma of the spermatic cord. To our knowledge, this is the 5th case reported in Japan.