A two wavelength laser module is made up of a semiconductor laser assembly that includes a first semiconductor laser for emitting a first light beam of a first polarization direction and a second semiconductor laser for emitting a second light beam of a second polarization direction. The second light beam is emitted approximately in the same direction as that of the first light beam and has a shorter wavelength than that of the first light beam. The first and second semiconductor lasers are disposed on a substrate. The module includes a polarization diffraction element for causing a divergence angle of the first light beam to differ from that of the second light beam.