A 37-year-old female presented to our hospital with increasing intraabdominal cyst around common bile duct(CBD). On a contrast-enhanced abdominal computed tomography scan(A-P CT), the cyst was located just right side of CBD and increased to 8.5cm during 5years. The first diagnosis was choledochal cyst (type I vs. type II) or lymphangioma. Initially, we performed endoscopic ultrasonographic aspiration with cytology. The aspirated fluid of cyst was serous and the amount was 55cc. On 4 months later followed-up A-P CT scan, the size was 6cm. we performed laparoscopic cyst excision. The final diagnosis was retention cyst of pancreatic head. The patient was discharged on postoperative day 7 without complication. We describe an retention cyst of pancreatic head mimiking choledochal cyst with managed successfully by laparoscopic cyst excision.