An optical writing apparatus includes: a light source panel including light emitting elements arranged on an elongate glass substrate; an optical member that causes emergent light to form an image; a first holding member holding the optical member; and a second holding member holding the glass substrate, wherein legs are provided below the first holding member on sides of both ends, the legs extending downward, drooping ends of the legs being mounted and fixed on the second holding member, one end of the glass substrate is positioned inside the space, an integrated circuit being provided, a through hole is provided to an upper surface of the second holding member, and when cooling air for the integrated circuit flows into the space, the cooling air is guided through the through hole to a side of a lower surface of the upper surface of the second holding member.