A 62-year-old man was referred to our hospital with complaints of upper abdominal pain and weight loss while being treated for diabetes mellitus at his family doctor. He was diagnosed as locally advanced unresectable pancreatic adenocarcinoma that involved superior mesenteric artery(SMA). Gemcitabine(GEM)and S-1 combined chemoradiotherapy(CRT) was administered. After CRT, CT test showed improved involvement of SMA, and radical resection was possible. We performed the radical pancreaticoduodenectomy and adjuvant chemotherapy, and he has been followed up for more than 5 years after the operation without recurrence. For locally advanced unresectable pancreatic adenocarcinoma, CRT or chemotherapy is recommended in the Pancreatic Cancer Practice Guidelines(2019 edition). However, the prognosis is extremely poor. We report a case of locally advanced unresectable pancreatic adenocarcinoma that was successfully curatively resected due to the good response of CRT.