Rhabdomyosarcoma of the prostate is a rare mesenchymal tumor that originates from undifferentiated mesenchymal cells. Spindle cell rhabdomyosarcoma is a variant of embryonal rhabdomyosarcoma. The vast majority of these two pathological types occur in children, with only a few adult cases reported to date, and both are associated with poor clinical outcomes. We herein report a case involving a man in his early 40s with spindle cell embryonal rhabdomyosarcoma of the prostate. His chief complaint was difficult urination. The diagnosis was confirmed by puncture biopsy of the prostate, and pelvic lymph node metastasis was already present at the time of diagnosis. The patient underwent three courses of chemotherapy. However, his response to the treatment was very poor, and he died of the disease 4 months after diagnosis.