A structure which increases positioning precision of a blade member to a rotating member, an image forming apparatus, and a method of manufacturing a unit frame. A first reference surface of a boss provided on a surface of a frame to which a blade is contacted is formed by a first mold that forms a positioning hole for positioning a rotating member. The first reference surface supports the blade member to prevent the blade member from moving to a weight direction. With this arrangement, there is no manufacturing error of the first reference surface due to a mold assembling error. As a result, precision of positioning the blade member to the rotating member can be increased.