A 79-year-old man was admitted to our hospital to determine the cause of his melena. He underwent esophagogastric endoscopy and computed tomography, revealing a submucosal tumor on the anterior wall of the gastric antrum with multiple liver metastases. Endoscopic biopsy revealed a large cell neuroendocrine cell carcinoma. A subtotal gastrostomy was performed to prevent pyloric stenosis and anemia caused by tumor hemorrhage. Previous studies on gastric neuroendocrine carcinoma reported poor prognosis. Large- and small-cell types of gastric neuroendocrine carcinomas were differentiated for the first time in the 14th edition of the Japanese Classification of Gastric Carcinoma. It is expected that the number of reports of gastric neuroendocrine carcinomas classified as either the large-cell or small-cell type will increase. It is necessary to collect information on more cases to improve prognosis and to establish appropriate treatment guidelines.