We have experienced a case of small early mucosal gastric cancer with lymph node metastasis. The patient was a 75-year-old woman diagnosed as having early gastric cancer type 0 IIa on the greater curvature of the antrum. We performed distal gastrectomy, with Billroth I method reconstruction. The tumor lesion was on the greater curvature of the antrum. Metastasis was discovered in the number 4d lymph node, histologically. The tumor was type 0 IIa confined to the mucosa, 1.0 cm in diameter and differentiated histological type, and no ulcer scar could be seen in tumor lesion. However, the tumor was massively invading to the mucosal membrane, with positive lymph vessel invasion, and was of mixed histological type. This was a rare case of small early mucosal cancer 1.0 cm in diameter with lymph node metastasis.