Here we report the case of a 73-year-old male who had undergone esophagogastroduodenoscopy (EGD) at a nearby hospital or at our hospital every year since 2006. In 2013, EGD results revealed a discolored lesion, measuring 6mm in diameter, on the anterior side of the upper body in the stomach. Helicobacter pylori (HP) was eradicated in 2010, and the background mucosa around the lesion was endoscopically diagnosed as non-atrophic. We performed endoscopic biopsy of the lesion. Histological examination of the specimen confirmed gastric adenocarcinoma of the fundic gland type. Based on the findings of EGD, ultrasonic endoscopy, and upper gastrointestinal series, we diagnosed that the infiltration of the adenocarcinoma was limited to the mucosa. Hence, we performed endoscopic submucosal dissection (ESD). After ESD, the resected cancer was located in the mucosa and no invasive lesion was detected at any vessels. Therefore, complete resection was performed through ESD. Retrospectively, the lesion could be detected in the endoscopic images taken in 2006. The shape and diameter of the lesion did not seem to have significantly changed from 2006 to 2013. In this case, slow tumor progression was observed. In 2015, no new lesions in the stomach or metastatic area were detected. Here we report a rare case of gastric adenocarcinoma of the fundic gland type that showed very slow progression.