Bleeding from the appendix is a very rare cause of bleeding in the colon that is easily missed because conventional colonoscopy often fails to directly image the inside of the appendix. In this case, a 53-year-old man was admitted with sudden onset of bleeding in the stool, with the first colonoscopy revealing blood in the colon of no identifiable source. Computed tomography showed an enlarged appendix approximately 10 mm in diameter without signs of acute inflammation. When the bleeding recurred, a second colonoscopy identified a suspected diverticulum in the cecum, but examination revealed active bleeding from the appendix opening. Doctors then used a disposable imaging catheter (EyeMax) that allowed direct visualization of the inside of the appendix and confirmed the presence of blood clots and ongoing bleeding. The patient underwent a laparoscopic operation to remove the appendix, while the histopathological examination revealed chronic appendicitis with a mucosal ulcer. The patient recovered well after surgery and no further bleeding occurred during the 6-month follow-up. This minimally invasive technique with a disposable imaging catheter represents a new diagnostic option for identifying rare cases of appendiceal bleeding.