Prognosis of pancreas cancer is extremely poor. For unresectable pancreas cancer, there has not been an effective method of treating. In our institution, the mean survival time was 13 . 6 months for a chemoradiotherapy case that used gemcitabine (GEM), but was 7.3 months for a non-treatment case in locally advanced and metastatic pancreas cancer. This time, we experienced a good case for unresectable pancreas cancer treated with chemoradiotherapy using GEM/S-1 that clearly exhibited a decrease in tumor size by tumor marker.