A 23-year-old man with a history of anemia of unknown cause was referred to our hospital. He had experienced melena three times: at 6months, 10years, and 20years of age. He underwent upper and lower gastrointestinal endoscopy at 10 and 20years of age, and small intestinal capsule endoscopy twice at 20years of age, but the site of bleeding could not be identified. At first, a transabdominal ultrasound was performed for suspected Meckel's diverticulum. A cystic diverticulum was found in the ileum, with an apertural diameter of 5mm and a total size of 4cm. The cyst showed an area of loss of wall stratification, which appeared to be an ulcer scar. Based on these observations, we diagnosed anemia resulting from a hemorrhagic Meckel's diverticulum and performed laparoscopic resection. Postoperative histopathology revealed ectopic gastric mucosa and ulcer formation within the Meckel's diverticulum, which was thought to be the cause of the bleeding. Meckel's diverticulum should be considered in cases of hemorrhage in young patients. A transabdominal ultrasound as a screening test detected a diverticulum with an ulcer scar in the ileum, which led to the identification of the underlying disease.