First eccentric cams for abutting an inner circumferential surface of an intermediate image transferring belt, second eccentric cams for rotating as a unit with the first eccentric cams, cam followers for abutting a circumferential surface of the second eccentric cam, and transmitting members for holding image transferring rollers, moving in response to the cam followers are disposed within a loop-shaped moving path formed by an intermediate image transferring belt, which is stretched across a driving roller and a driven roller. The vertical position of the image transferring rollers, which are held by the transmitting members, changes in accordance with the abutting state of the first eccentric cams with respect to an inner circumferential surface of the intermediate image transferring belt.