Abstract: A cylindrical anal retractor for examining the inside of an anus of a living body including an inserting valve portion inside of which a substantially circular-shaped opening is formed, a handle which serves to dilate the opening by gripping it, and an auxiliary appliance for making the insertion of the inserting valve portion into the anus smooth; the trivalve inserting portion has three plate-like members, which are curved inside, and two of the members are connected to the handle so as to be rotatable about axes extended in an inserting direction of the inserting valve portion. In the anal retractor according to the present invention, therefore, the pain which is given to the patient when the anal retractor is inserted into his or her anus is remarkably reduced.