A semiconductor laser diode device with small driving current and no distortion in the projected image. The semiconductor laser diode includes an n-GaAs substrate and, an n-cladding layer on the n-GaAs substrate, an active layer, a p-clad layer, a multilayer formed from sequentially laminated p-contact layers, and a ridge formed by selectively etching from the upper surface of the p-contact active layer to a specified depth on the p-contact layer, and an insulating film deposited on the upper surface side of the n-GaAs substrate, and formed from the side surface of the ridge to the edge periphery of the n-GaAs substrate, and a p-electrode formed on the insulating layer deposited on the ridge of the P-contact layer, and an n-type electrode formed on the lower surface of the n-GaAs substrate; and the n-GaAs substrate structure possesses a side edge serving as an absorption layer to absorb light emitted at the active layer wavelength; and a groove is fabricated at the side edge forming the front facet (forward emission side), to a depth from the p-cladding layer exceeding the active layer, from a p-cladding layer section a specified distance away from the side of the ridge along the edge, to the side of the active layer; and the groove is covered by the insulating layer.