A periodic gain-type semiconductor laser device in which a mesa stripe has wide portions and narrow portions alternately arranged with a period that is an integral multiple of the half-wavelength of the emitted light. A multilayer structure including an n-AlGaAs first cladding layer 103 and an AlGaAs non-doped active layer 104 formed on the mesa stripe also have wide portions and narrow portions. An n-AlGaAs current confining layer 106 covers the sides of the AlGaAs non-doped active layer 104. The height of the top surface of the n-AlGaAs current confining layer 106 matches the height of the AlGaAs non-doped active layer 104. A p-AlGaAs second cladding layer 105 is formed on the AlGaAs non-doped active layer 104 and the current confining layer 106. A driving current is not injected into the narrow portions of the AlGaAs non-doped active layer 104.