An exposure device includes: a substrate that includes a plate-shaped main body that extends in one direction, a plurality of light emitting elements that are mounted on one surface of the main body, and a heating element that is mounted on the other surface of the main body generates heat in accordance with a light emitting operation of the light emitting elements; a housing that includes resin and that extends in the one direction, has a frame shape in which a through hole is formed, and to an inside of the through hole of which the substrate is fixed so that a thickness direction of the substrate is a penetrating direction of the through hole; and a suppression member that extends in the one direction, is fitted in the through hole, and suppresses thermal deformation of the housing.