An image forming apparatus includes an executing portion for cleaning a rotatable heating member by introducing, into a nip, sheets, of a plurality of sheets, on which a predetermined toner image is formed by an image forming portion, a changing mechanism for making positional relationships of first and second sheets, of the plurality of sheets, relative to the rotatable heating member, different from each other with respect to a widthwise direction of the rotatable heating member when the first and second sheets are successively introduced into the nip in a cleaning mode, and a re-introducing mechanism for re-introducing the first and second sheets into the nip, the first and second sheets having passed through the nip and having been turned upside down, wherein the changing mechanism changes the relative positional relationship of the first and second sheets, which are turned upside down, relative to the rotatable heating member.