The invention provides an annular body having an inner surface including a base material layer, the base material layer having a resin and a conductive agent, and the inner surface comprising a carbonized region. The invention further provides an annular body stretching device having: the annular body; and a stretching unit pushing outward the annular body with tension from an inner circumferential side of the annular body. The invention further provides an image forming apparatus having the annular body as an intermediate transfer body provided thereto. The invention further provides a method for forming the annular body, having forming a carbonized region by a process to give conductivity to the inner surface of the annular body.