Plural collimator lenses are arranged corresponding to plural laser light sources to collimate light beams emitted from the laser light sources into substantially parallel light beams, respectively. A condenser lens focuses the substantially parallel light beams. A coupling optical element, on which light beams focused by the condenser lens are incident, couples the light beams into a single light beam. The laser light sources are arranged such that a longitudinal direction of an emitting region of each of the laser light sources is coincident with a radial direction of the condenser lens.