This semiconductor laser device includes a semiconductor laser chip and a spatial light modulator SLM which is optically connected to the semiconductor laser chip. The semiconductor laser chip LDC includes an active layer 4, a pair of cladding layers 2 and 7 sandwiching the active layer 4, and a diffraction grating layer 6 which is optically connected to the active layer 4. The spatial light modulator SLM includes a transparent common electrode 25, a plurality of transparent pixel electrodes 21, a liquid crystal layer LC arranged between the common electrode 25 and the pixel electrodes 21. A laser beam output in a thickness direction of the diffraction grating layer 6 is modulated by the spatial light modulator SLM, passes therethrough, and is output to the outside.