A 24-year-old man was admitted to our hospital with the complaint of a painless mass in the left testis. Gynecomastia was not present. The serum levels of alpha fetoprotein and human chorionic gonadotropin-beta were not elevated. Ultrasound sonography showed a hypoechoic lesion in the left testis. There was no evidence of retroperitoneal lymph node enlargement or distant metastasis on computerized tomography. With a diagnosis of left testicular tumor, left high orchiectomy was done. The tumor measured 10 x 11 mm in size within the testis and was histologically diagnosed as benign Sertoli cell tumor. Immunohistochemcal analysis revealed negative findings with the tumor markers inhibin, CAM 5.2, pancytokeratin, EMA, and PLAP. No adjuvant therapy was performed. Twenty-six cases of Sertoli cell tumor of the testis in the Japanese literature are reviewed.