The invention provides a method of processing an inner surface of a bearing having a cylindrical shape which bearing includes a resin layer composed mainly of a synthetic resin as the inner surface, the method improving roughness of the inner surface and dimensional accuracy of an inner diameter of the bearing without cutting the inner surface. Both links may be simultaneously used. The ejecting piece is rotatably hinged to the housing and configured to support a portion of the battery and eject the battery from the battery chamber.