A laser light source device comprising: a laser light source configured to combine a plurality of laser beams, each of a same given colour, to emit a laser-beam bundle; a homogenizer configured to remove or reduce coherence of the laser-beam bundle emitted from the laser light source by randomly modifying the wavefront of the laser-beam bundle; an optical system configured to emit the laser-beam bundle that has passed through the homogenizer ; a beam splitter arranged between the homogenizer and the optical system and configured to branch a part of the laser-beam bundle that is guided from the homogenizer to the optical system, as a for-detection laser-beam bundle (LS); a photosensor including a plurality of photodetectors configured to receive the for-detection laser-beam bundle (LS) branched by the beam splitter ; and a light emission controller configured to control light emission of the laser light source based on outputs from the plurality of photodetectors of the photosensor to terminate or reduce light emission when an output of at least one of the photodetectors exceeds a threshold value the laser light source device being characterised in that said plurality of photodetectors are arranged so as to be proximate to each other, the laser light source device being further characterised in that the output of each photodetector of said plurality of photodetectors is compared with the threshold value before the termination or reduction of light emission when an output of at least one of the photodetectors exceeds a threshold value, or further in that the the light emission controller is configured to control light emission of the laser light source based on outputs of the plurality of photodetectors of the photosensor to terminate or reduce light emission when a difference between outputs of two or more of the photodetectors exceeds a prescribed amount. a laser light source configured to combine a plurality of laser beams, each of a same given colour, to emit a laser-beam bundle; a homogenizer configured to remove or reduce coherence of the laser-beam bundle emitted from the laser light source by randomly modifying the wavefront of the laser-beam bundle; an optical system configured to emit the laser-beam bundle that has passed through the homogenizer ; a beam splitter arranged between the homogenizer and the optical system and configured to branch a part of the laser-beam bundle that is guided from the homogenizer to the optical system, as a for-detection laser-beam bundle (LS); a photosensor including a plurality of photodetectors configured to receive the for-detection laser-beam bundle (LS) branched by the beam splitter ; and a light emission controller configured to control light emission of the laser light source based on outputs from the plurality of photodetectors of the photosensor to terminate or reduce light emission when an output of at least one of the photodetectors exceeds a threshold value the laser light source device being characterised in that said plurality of photodetectors are arranged so as to be proximate to each other, the laser light source device being further characterised in that the output of each photodetector of said plurality of photodetectors is compared with the threshold value before the termination or reduction of light emission when an output of at least one of the photodetectors exceeds a threshold value, or further in that the the light emission controller is configured to control light emission of the laser light source based on outputs of the plurality of photodetectors of the photosensor to terminate or reduce light emission when a difference between outputs of two or more of the photodetectors exceeds a prescribed amount. <EOS>