An image forming apparatus includes an image forming unit, a belt, tension rollers, a pressing member, a support member, and an adjustment member. The pressing member is brought into contact with an inner circumferential surface of the belt and, from the inner circumferential surface, presses the belt against an outer circumferential surface of the belt and extending along a longitudinal direction corresponding to a width direction of the belt. A tip of the pressing member is brought into contact with the inner circumferential surface. The adjustment member is fixed such that a position with respect to the pressing member is adjustable in a short direction orthogonal to a longitudinal direction of the pressing member, and adjusts a length of a protruding portion of the pressing member protruding from the adjustment member toward the downstream in a movement direction of the belt.