This is a case presentation of a unique cause of intestinal bleeding. A duodenal ulcer eroded into the superficial branch of the cystic artery, causing massive intestinal hemorrhage. The patient, a 76-year-old woman, presented with left upper abdominal and left back pain secondary to cystic lesions in the pancreas body and tail. Stress after operation and complication of leakage of pancreatic juice after distal pancreatectomy with splenectomy and diclofenac sodium administration may have caused a deep peptic ulcer to erode the cystic artery. We performed a transfixing ligation of the bleeding vessel, serosal suture of ulcer of the gallbladder, and simple closure of the duodenal ulcer with covering greater omentum. There were no serious complications after the operation, and the patient made an uneventful recovery.