A 57-year-old man was diagnosed with a tumor in the pancreatic body at a nearby hospital and consulted our hospital. Examinations revealed that carbohydrate antigen 19-9(CA19-9)levels were 1,765.0 U/mL. We confirmed metastatic liver tumors in S4 and S8 of the liver by EOB-MRI. We diagnosed unresectable pancreatic cancer(T3N0M1, cStage Ⅳ)and administered 10 courses of gemcitabine(GEM)plus nab-paclitaxel(nab-PTX)therapy. The main lesion and the lesion in S4 subsequently disappeared, and the lesion in S8 degenerated into a cyst. CA19-9 levels were 113 U/mL. Surgery was determined as the best course of action after normalizing CA19-9 levels. Therefore, we further administered 6 courses of FOLFIRINOX therapy and 4 courses of GEM plus nab-PTX therapy, but CA19-9 was not normalized. We decided that it would be difficult to normalize CA19-9, and thus proceeded with surgery. During the operation, cystic degenerative lesions were found in S8 and peritoneal dissemination was found in the transverse mesentery. Because the ascites cytopathology was negative, it was judged that the peritoneal dissemination was localized. We performed distal pancreatectomy(D2)plus partial hepatectomy(S8)plus peritoneal dissemination resection. On day 52 after surgery, we resumed GEM plus nab-PTX. The patient has survived without any recurrence for 3 years after the initial surgery.