A laser light source according to the present invention includes a laser element that outputs a fundamental wave; a wavelength conversion element into which the fundamental wave is input and that converts at least a part of the fundamental wave input therein to a converted wave having a wavelength shorter than the wavelength of the fundamental wave; a waveguide that attenuates a component of the fundamental wave included in an output wave from the wavelength conversion element; and a diffraction grating that is formed on the waveguide and feeds back the fundamental wave output from the wavelength conversion element to lock the wavelength or the frequency of the fundamental wave output from the laser element. The diffraction grating is formed at a position determined taking into account an amount by which the fundamental wave is attenuated in the waveguide.