An image forming apparatus includes a photoreceptor which is rotatable with respect to a body frame, an exposing member which is movable relative to the body frame, a spacing member which is provided between the exposing member and the photoreceptor to maintain a distance between the photoreceptor and the exposing member, a positioning member which makes a contact with the exposing member to position the exposing member in a direction of rotation of the photoreceptor, and a pressing member which is provided to the body frame to press the exposing member toward the photoreceptor and the positioning member. Accordingly, it is possible to position the exposing member accurately with respect to the photoreceptor, in any of the light-axis direction and the rotational direction of the photoreceptor.