Abstract A choledochocele (type 3 choledochal cyst) is rarely observed in children. A 6-year-old boy experienced abdominal pain approximately 6 times in the previous 5 months. Magnetic resonance cholangiopancreatography findings revealed a small cyst in the distal common bile duct. An endoscopic examination was performed, and a choledochocele was detected at the duodenal papilla. Endoscopic unroofing was successfully performed, and the postoperative course was uneventful.