Abstract: The present invention relates to a two-wavelength semiconductor laser device, more particularly, to a fabrication method of a multi-wavelength semiconductor laser device. In this method, a substrate having an upper surface separated into at least first and second areas is provided. Then, a first dielectric mask on the substrate is formed to expose only the first area. Then, epitaxial layers for a first semiconductor laser are grown on the first area of the substrate. Then, a second dielectric mask on the substrate is formed to expose only the second area. Then, epitaxial layers for a second semiconductor laser are grown on the second area of the substrate.