The patient was a 70-year-old man. The patient had progressive anemia while taking 10 mg/day of prednisolone and 100 mg/day of mizoribine orally for bullous pemphigoid, a colonoscopy diagnosed ascending colon cancer. Adenocarcinoma, Group 5 was detected on biopsy. Abdominal computed tomography showed no metastases. The tumor was diagnosed as ascending colon cancer, cT4aN0M0, cStage Ⅱb. We performed laparoscopic right hemicolectomy and D3 dissection. Histopathological examination revealed pT3N0M0, pStage Ⅱa. In the present report, we describe a case of the ascending colon cancer with bullous pemphigoid, and discuss the case with a review of the literature.