A laser light source includes a laser element that outputs a fundamental wave; a wavelength conversion element to which the fundamental wave is input and that wavelength-converts at least a portion of the input fundamental wave to a converted wave having a wavelength shorter than the fundamental wave; a first waveguide that guides an output wave from the wavelength conversion element; a second waveguide that attenuates and guides a component of the fundamental wave included in the output wave from the first waveguide; a diffraction grating that is formed in the first waveguide and locks a wavelength or a frequency of the fundamental wave output from the laser element by feeding back the fundamental wave output from the wavelength conversion element.