A 67‐year‐old man with upper abdominal pain and weight loss was diagnosed as having 3/4 circumferential mass of advanced gastric cancer extending to gastric lesser curvature （cT4aN1M0 stage IIIA）. After confirming the absence of peritoneal dissemination by laparoscopy, neoadjuvant chemotherapy （SOX） was started to reduce the size of the gastric cancer. After one course, the patient vomited and was judged to have clinically advanced, unresectable gastric cancer. His regimen was changed to CapeOX ＋ T‐mab. In addition, a W‐ED® tube, which has a double‐tube structure and can perform gastric decompression and enteral nutrition, was placed. Enteral feeding could be performed without vomiting. The patient was discharged from the hospital after completion of one course, and after home nutritional management and two courses of outpatient chemotherapy, he underwent gastrectomy and was discharged from the hospital without any postoperative complications. The pathological diagnosis was ypT4aN0M0 stage IIb. He received adjuvant chemotherapy （S‐1） and was alive at 1 year and 3 months without recurrent disease. The maintenance and improvement of nutritional factors during the course of multidisciplinary treatment was considered to be extremely important for the performance of surgery.