An image forming apparatus has an image forming section (40Y, 40M, 40C,40K) having a photoreceptor (41) on which a toner image is formed, an endless belt (51) that revolves with its outer surface facing the photoreceptor, a steering roller (58) adapted to provide a tension to the belt and adjust the position of the belt in the width direction, a transfer roller (52Y, 52M, 52C, 52K) that presses the belt toward the photoreceptor so as to form a transfer nip where the toner image is transferred, a transfer pressure adjusting mechanism (122)adapted to adjust pressing force when the transfer roller presses the belt toward the photoreceptor, and control the pressing force adjusted by the transfer pressure adjusting mechanism, according to the adjustment state of the steering roller.