We report a case of primary small cell carcinoma of the urinary bladder. A 74-year-old woman was referred to our hospital because of pollakiuria. Cystoscopy showed a papillary tumor. We operated transurethral resection of the bladder tumor (TUR-Bt). Histopathological finding was transitional cell carcinoma (TCC), grade3, pT1 containing pTis. About six months later, tumor recurred to the bladder. Pathologic diagnosis was TCC in part and most was small cell carcinoma. Pelvic magnetic resonance imaging revealed a huge mass lesion with extravesical extension in the urinary bladder, and computed tomography scan showed external iliac lympho node metastasis. The rapid rise of a tumor maker NSE and pro-GRP were remarkable. It was diagnosed as a rapid advance of small cell carcinoma. We performed pelvic radiotherapy, and chemotherapy using carboplatin (CBDCA) and etoposide (VP-16). However 14 months after it had left hospital, computed tomography showed paraaortic lympho node metastasis. The patient died due to rapidly progressive disease.