Standard transanal excision of the rectal polyps is curative and is less invasive than transsacral resection or low anterior resction, but it is difficult to resect tumors that are distant from the anal verge. Moreover, in the case of large polyps, the risks of complications, such as hemorrhage or perforation, increase because exposure on the oral side of the tumor is poor. If exposure can be improved, transanal excision can be performed safely and completely when the polyp is large and distant from the anal verge. We used transsacral manual assistance to achieve transanal resection of a large tubulovillous adenoma of the rectum that was hard to be resected using the traditional transanal approach.