A pipe bender includes an actuating handle having an actuating element movably installed at the actuating handle and controllable to move in order to extend in an axial direction of the actuating handle, and a support arm transversally spanned over the actuating handle and having a support device disposed at both ends of the actuating handle separately and slidable along the support arm. Each support device includes a base with a grip portion, and a grip space formed in the grip portion, and the base is sheathed from the grip space on the support arm through the grip portion, and the support device includes a positioning mechanism for sliding and moving the support device to a selected position and then positioning the support device on the support arm.