We report a case of early gastric cancer resembling submucosal tumor due to marked venous infiltration. A 68-year-old man was pointed out an abnormality of the stomach in a medical checkup. Radiological findings revealed a submucosal tumor-like lesion measuring about 1.5cm with central concavity in the body of the stomach. We diagnosed the case as early gastric cancer and performed a segmental gastrectomy. Histologically the tumor was diagnosed as poorly differentiated adenocarcinoma {porl, pT1 (SM), med, INF α, ly0, v3, and pNO}. The submucosal tumor-like appearance was due to marked venous infiltration in the submucosa. The postoperative course was uneventful. The patient is living and well as of 10months after the operation.