An exposure apparatus includes a light source that emits a plurality of light beams, a substrate on which the light source is mounted, a positioning member provided on a housing and being in contact with a positioning surface provided around the light source to position the light source with respect to the housing in an optical axis direction, the housing accommodating an optical system that guides the light beams, and an attachment member attached to the housing and including a portion that extends in a direction substantially perpendicular to the optical axis direction and that is bent over, an end of the bent portion being attached to the substrate such that the positioning surface around the light source is urged against the positioning member and the substrate is attached to the housing.