An exposure device according to an embodiment includes: a substrate in which light-emitting elements are mounted; an optical system which converges light emitted from the light-emitting elements; a holding member includes a holding member body which holds the substrate and the optical system, and a cut fringe projected from the holding member body; and a support member provided at a predetermined position in the holding member between the substrate and the optical system. The support member is formed of a cured agent attached to a shear surface of the cut fringe of the holding member, and the support member includes a contact surface with which the substrate is in contact.