To obtain a laser beam synthesizer which can efficiently synthesize laser beams with a simple structure and at low cost.

The laser beam synthesizer comprises a plurality of laser light sources 11 having anisotropy in the angle of laser beam radiation, collimator lenses 12 which are arranged to the laser light sources 11 one to one and form into parallel light each laser beam emitted from the laser light sources 11, condenser lenses 13 which condense the luminous flux of the laser beams made into parallel light by each collimator lens 12, and a synthesis optical element 14 which makes enter the luminous flux of the laser beams condensed by the condenser lenses 13 for synthesis. The laser light source is arranged so that the longitudinal direction of a light emission region of the laser beams may correspond to the radial direction of the condenser lenses 13.