A man in his sixties presented to our hospital with obstructive jaundice and was diagnosed with inoperable pancreatic cancer. Chemoradiotherapy was initiated, and an expandable metallic stent was inserted endoscopically to drain the biliary system. Six months later, he was referred to our hospital with 1-week history of epigastric pain and obstructive jaundice. On admission for further evaluation, he experienced hematemesis and went into severe shock. Upper gastrointestinal endoscopy and endoscopic retrograde cholangiopancreatography showed active bleeding from the duodenal papilla. Therefore, we performed endoscopic nasobiliary drainage (ENBD). On day 4, blood was detected in the ENBD tube, and the patient again experienced hematemesis. Emergent enhanced computed tomography revealed a right hepatic arterial aneurysm that had likely ruptured and caused the hemobilia. The aneurysm was successfully embolized, and the patient was discharged on hospital day 21.