A laser source unit obtains Q switch pulse oscillation with a simple structure while continuously switching a plurality of wavelengths. A laser source unit emits pulsed laser beams with a plurality of different wavelengths. A flash lamp radiates excitation light to a laser rod. A pair of mirrors face each other with the laser rod interposed therebetween. The pair of mirrors form an optical resonator. Wavelength selection means controls the wavelength of light which resonates in the optical resonator to any one of a plurality of wavelengths to be emitted by the laser source unit. Driving means drives the wavelength selection means such that the optical resonator performs the Q switch pulse oscillation.
