A semiconductor laser array device comprising a substrate; an index-waveguiding area positioned on said substrate; a Fourier-converting area, which is adjacent to said waveguiding area and in which laser lights emitted with synchronized phases from said waveguiding area undergo the Fourier-conversion, positioned on said substrate; and a reflecting mirror, which is adjacent to said Fourier-converting area and by which said converted laser lights with a 0.degree.-phase shift mode are selectively reflected so as to be incident upon said waveguiding areas.