We report a case of human epidermal growth factor receptor 2(HER2)-positive advanced gastric cancer successfully treated with combination therapy of trastuzumab, capecitabine, and cisplatin, followed by a curative resection. A 23-year-old woman was diagnosed with advanced type 3 gastric cancer, and the clinical findings were T3N0M0, StageIIA. A laparoscopic exploration revealed that it was a CY1 unresectable StageIV cancer. Initially, docetaxel, cisplatin, and S-1 therapy was chosen. However, the patient's HER2 status proved to be positive (IHC 3+), and so trastuzumab, capecitabine and cisplatin therapy was administered. After four cycles, the tumor significantly decreased in size, suggesting a partial response(PR). A further laparoscopic exam showed no apparent dissemination or metastatic cancer cells. We performed a curative resection consisting of a laparoscopic distal gastrectomy and D2 lymphadenectomy. The patient's postoperative course has been uneventful. She has been alive for 4 months and is receiving adjuvant chemotherapy comprising trastuzumab and S-1.