A seventies age man was admitted complaining of epigastric pain. Computed tomography of the abdomen showed the fluid collection and inflammation in the retroperitoneal space besides pancreas. We suspected acute pancreatitis, and started the treatment by the medications. However, the treatment was not effective. Because we suspected of perforation, we underwent the operation. In the operation, there was a large amount of bile in the retroperitoneal space. We performed intraperitoneal drainage because of uncertain cause. After the operation, he got worse, and died on the ５５th day. The autopsy showed the biliary fistula at right hepatic duct to the retroperitoneal space. The biliary fistula to the retroperitoneal space was very rare case, therefore we must understand the pathological condition due to save the life
