In this paper, we reported a case of congenital aplasia of dorsal pancreas. This case in 35th case in Japan. The case is 72-year-old male. He feels general fatigability as chief complaint and was taken Diabetes Mellitus. In ERP examination, it was found a short main pancreatic duct of about 4.5 cm length and defect of pancreatic body and tail in Ultrasonogram and Computed Tomogram. In arteriography, it was not found feeding artery to pancreatic body and tail. Accordingly, we diagnosed this case as congenital defect of pancreatic body and tail. This one was normal range for P. F. D. andnormal exocrine pancreatic function. But, this one was operated because of taking cholecystolithiasis. On Retroperitoneal space that shoud be originally pancreatic body and tail, we confirmed only fat tissue without inflammation, fibrosis and carcinomatous tissue. We could not be confirmed Langerhans islet and pancreatic tissue in the biopsy sections of fat tissue.