To obtain a laser unit light source which is provided with a laser light source capable of emitting linearly polarized light, a polarization separating element capable of selecting an optical path by the polarization state of a laser beam, and a light receiving element capable of receiving the laser beam and which is made thin and low-cost, and to obtain a laser unit light source which can deal with many wavelengths and be made low-cost.

The laser unit light source is provided with the laser light source capable of emitting the linearly polarized light, the polarization separation element capable of selecting the optical path by the polarization state of the laser beam, and the light receiving element capable of receiving the laser beam. In the laser unit light source, an optical element which can control the light spreading angle of the laser beam emitted from the laser light source is arranged between the laser light source and the polarization separating element.