The patient was a 71-year-old male who underwent laparoscopic cholecystectomy. Preoperative ERCP (Endoscopic Retrograde Cholangiopancreatography) and MRCP (Magnetic Resonance Cholangiopancreatography) did not reveal any obvious biliary tract anomalies. However, during surgery, a vascular structure was observed while dissecting the dorsal side of the gallbladder. The blade of the ultrasonic coagulation and cutting device came into contact with this structure, resulting in bile leakage. The posterior sectoral hepatic duct was found to merge with the common bile duct dorsally, distal to the confluence with the cystic duct. The damaged site was sutured and closed with 4-0 non-absorbable sutures. An accessory hepatic duct is a biliary tract anomaly in which an intrahepatic bile duct supplying a subsegmental liver region courses extrahepatically and drains into the common hepatic duct, common bile duct, gallbladder, or cystic duct. It is crucial to thoroughly evaluate the biliary anatomy preoperatively. Additionally, the surgeon must be well-versed in repair techniques and biliary reconstruction procedures.