A 67-year-old man presented complaining of an upset stomach. On upper gastrointestinal endoscopy, an irregular elevated lesion was seen near the gastric cardia, which was diagnosed by biopsy as poorly differentiated adenocarcinoma. Total gastrectomy and D2 lymph node dissection were performed. Histopathological investigation resulted in a diagnosis of pStage IIb large-cell gastric neuroendocrine carcinoma. Combination carboplatin and irinotecan therapy was given as postoperative adjuvant chemotherapy. Two years postoperatively, a solitary brain metastasis was identified and treated by stereotactic radiotherapy with a CyberKnife. Treatment for this brain metastasis was subsequently performed repeatedly. Around 3 years 10 months postoperatively, the patient also developed normal-pressure hydrocephalus, and a lumboperitoneal shunt procedure was performed. He died of the original cancer at 4 years 2 months postoperatively. No lymph node or other distant metastasis was observed during the clinical course. This extremely rare case of solitary brain metastasis of large-cell gastric neuroendocrine carcinoma is reported along with a short discussion of the literature.