Hemangioma of the small intestine is rare, and the preoperative diagnosis of it is difficult. We report a patient with gastrointestinal bleeding for whom Tc-99m-labeled red blood cell scintigraphy was useful in diagnosing cavernous hemangioma of the small intestine. A 25-year-old man was referred to our hospital for recurrent iron deficiency anemia. Because of the patient's severe anemia, imaging was performed to locate the bleeding lesion in the gastrointestinal tract. Scintigraphy with Tc-99m-labeled red blood cells revealed pooling indicating a tumor and extravasation of blood from the tumor. Scintigraphy with Tc-99m pertechnetate revealed no abnormal accumulation. Partial resection of the small intestine was done, and cavernous hemangioma of the small intestine was diagnosed by using the specimen of resected tissue.