Background and Aim Looping is a major problem in colonoscopy, and it prolongs procedure time. We evaluated the efficacy and safety of an external abdominal compression device (back brace support belt; Maxbelt) with respect to cecal insertion time and other outcomes. Methods We performed a prospective study on outpatients undergoing elective colonoscopy in Toyoshima Endoscopy Clinic. Subjects were randomly assigned to groups and were subjected to either Maxbelt (n = 39) or no device (control, n = 38) during colonoscopy. The colonoscopist was blinded to the study. The primary outcome that was observed was insertion time. Results The intubation time of the Maxbelt group was shorter than that of the no device group, but the difference was not significant (3.29 vs 4.49 min, P = 0.069). After stratifying by age, the use of Maxbelt significantly decreased cecal intubation time in elderly participants (age ≥ 45) compared to no device group (3.27 vs 5.00 min, P = 0.032). The use of the Maxbelt significantly decreased insertion difficulty encountered by the colonoscopist (P = 0.01). There was no difference in adenoma detection rate, manual pressure, position change, and adverse event. Conclusions The use of a back brace support belt could be a viable approach for colonoscopy in elderly patients. (University Hospital Medical Information Network: UMIN000029361).