A 72-year-old man was admitted with a chief complaint of fever and bloody feces. Rectal cancer was detected with colon fiber, and hematuria and abdominal pain appeared. Fluid-filled tissue in the corpus spongiosum and the rectum were detected by computed tomographic scan and magnetic resonance imaging, indicating that the abscess with necrotized tissue developed in them. Perineal skin and tissue were incised to drain and debride the necrotic tissue, which revealed that a drop of pus and the necrotic tissue were limited in the corpus spongiosum. Based on the imaging findings and the intraoperative findings, we finally diagnosed it as abscess of corpus spongiosum. Then we set a drainage tube around corpus spongiosum and closed the incision. The postoperative course was uneventful, followed by a second operation for the treatment of the rectal cancer. To our knowledge, this is the first report of abscess of corpus spongiosum.