Parasitic eosinophilic granuloma is a disease caused by migration of Anisakis species larva in the alimentary tract. Diagnosis is made pathologically by a lamellated structure consisting of a necrotic center with or without the worm, surrounded by layers of granulation tissue and eosinophilic infiltration. Recently, a 40-year-old male was admitted due to melena. Esophagogastroduodenoscopic examination revealed an irregularly shaped ulcer in the duodenal bulb and a large, lobulated elevated mass with an intact mucosal surface, suggesting a submucosal tumor, in the stomach. Endoscopic ultrasonography revealed an ill-defined hypoechoic mass involving submucosa, proper muscle, and serosa. Surgery was necessary for resection of the lesion because of the possibility of a malignant submucosal tumor. Pathological examination revealed an eosinophilic granuloma involving the submucosa, muscle, and serosa, and the presence of the larva, which had the characteristics of the Anisakis species: two lateral cords, eosinophilic cuticle, and well developed musculature.