A laser system is constructed so that a solid-state laser beam emitted from an Nd:YAG laser unit and a laser diode beam emitted from a combining LD which oscillates in a wavelength range shorter than that of the solid-state laser beam are combined by a dichroic beam splitter, the resultant beam is guided to an optical fiber, and a workpiece is irradiated with the combining LD beam and the solid-state laser beam with absolute irradiation positions and irradiation shapes of the beams almost matched each other. Thus, problems of high cost and high power consumption of the laser system due to low energy conversion efficiency, which become problems in a high-output high-luminance solid-state laser unit can be solved.