A 35-year-old man attended our hospital with complaining of epigastric pain and vomiting. He was diagnosed with bowel intussusception based on the target sign revealed in the upper jejunum by abdominal computed tomography. However, the cause of the intussusception was not clear. Insertion of an endoscope into the jejunum revealed prominent edema in the upper part of the jejunum, and Anisakis simplex was identified at the site and removed. Symptoms rapidly improved after endoscopic treatment. We report this case because surgery was avoidable and because we are aware of no previous reports of small intestinal intussusception caused by anisakiasis that has been diagnosed and treated endoscopically.