Variable wavelength laser light source

A highly stable variable wavelength laser light source of simple construction and having excellent productivity is provided. With the variable wavelength laser light source wherein a laser diode is provided with a non-reflection film on the front end face, and a high reflection film on the rear end face, outgoing light from the laser diode is condensed by a lens, branched out by a recombination and branching filter after falling thereon, and sent out to a wavelength selector selecting a light beam of a specific wavelength, which is returned to the laser diode via a recombination and branching filters and the recombination and branching filter and after condensed by the lens so that a laser beam is produced through resonance by the external resonator composed of an optical return path section and the high reflection film, and the laser beam is delivered from an output port via a recombination and branching filter.