An image forming apparatus comprising: a rotary body which rotates in accordance with an image forming operation; a rotation shaft of the rotary body; a through hole which is provided in an end portion in an axial direction of the rotation shaft; a stabilizing member which is provided to rotate together with the rotary body and stabilize the rotary body by reducing fluctuations of rotation of the rotary body under inertia, and which has an inserted portion into which the rotation shaft is inserted; a holding member which is disposed so as to be adjacent to the stabilizing member in the axial direction to hold the stabilizing member on the rotation shaft; a through hole which is formed in the longitudinal portion correspondingly to the through hole provided in the rotation shaft; and a clamp member which passes through the through hole provided in the longitudinal portion and the through hole provided in the rotation shaft.