Seventy-year-old man visited our hospital with general malaise and right lower abdominal pain. Lower intestinal endoscopy revealed some erosions and small ulcers in the terminal ileum. Small intestinal X-P was done for the purpose of further examination of erosions and ulcers revealing a worm of Ascaris lumbricoides of the jejunum. The patient was treated with pyrantel pamoate. Second lower intestinal endoscopy 2 months after the 1st endoscopy revealed the same erosions and ulcers in the terminal ileum and 2 white worms, about 5 mm in length, in the ascending colon. We diagnosed this worm as Enterobius vermicularis by the form and movement, and the egg. It is thought to be rare that Enterobius vermicularis is diagnosed endoscopically.