We describe a 72-year-old man admitted to hospital as an emergency case of epigastric abdominal pain. CT scan visualized massive hemorrhage around the pancreatic head. Computed tomographic angiography showed stenosis at the origin of the celiac artery and a 10 mm aneurysm of the posterior inferior pancreaticoduodenal artery (PIPDA). An emergency angiogram revealed a long aneurysm in the PIPDA. The aneurysm had irregular width and was 75 mm in length. A gastroduodenal artery and the PIPDA were supplied from the superior mesenteric artery. A transcatheter arterial embolization (TAE) was performed. We reviewed 45 cases of pancreaticoduodenal aneurysms after 2000 and cases of the pancreaticoduodenal false aneurysms after 1972. As a result, we inferred that this case without pancreatitis or pancreas surgery was a true aneurysm made by the bloodstream changes caused by the celiac artery stenosis.