Laser light from a light source part is guided to an irradiation plane by an irradiation optical system including element lenses and transparent parts. Light fluxes having passed through the element lenses respectively enter the transparent parts. A light condensing part superimposes irradiation regions of the light fluxes on the irradiation plane. When viewed in the arrangement direction of the element lenses, the light fluxes regarded as parallel light enter the light condensing part which includes a diverging lens for causing the parallel light to diverge in a Y direction perpendicular to the arrangement direction, and a converging lens for causing the light from the diverging lens to converge on the irradiation plane. This configuration readily achieves a design where the focal length of the light condensing part regarding the Y direction is reduced, and suppresses shifts in light condensing positions of the light fluxes on the irradiation plane.