An image forming apparatus includes a fuser unit which includes a heat roller and a pressure roller; a duct which is formed in a long shape in a direction along an axis of the heat roller, is disposed in the vicinity of the fuser unit along the axis of the heat roller, and is exhausted by an exhaust fan which is provided on one end side in a long-side direction; an exhaust port which is opened to a first side wall of the fuser unit side of the duct and causes the fuser unit and the duct to communicate with each other; and a planar filter which is attached to an inner wall surface of the duct. The filter includes a filter base material having an irregular surface shape in which ditches and convex portions are alternately disposed; and a frame which is bonded to both ends orthogonal to an irregularity direction of the filter base material, the convex portion of the filter base material protrudes from the frame, and the convex portion of the filter base material is bonded or stuck to the inner wall surface.