A surface-emitting semiconductor laser (VCSEL) having a structure in which the single horizontal mode of high power is stably maintained, and an optical device including a light-source device having this surface-emitting semiconductor laser are provided. A scattering-loss-structure portion composed of a low refractive-index region is disposed around a main current path in a surface-emitting semiconductor laser, namely around a cavity structure portion; the low refractive-index region is disposed at intervals; and the shape of the tip portion opposing to the center portion is set to be a tapered shape, for example, at an acute angle. Accordingly, in the cavity structure portion, the loss of light-emitting laser of a high-order mode localized in the outer circumferential portion becomes large, so that a surface-emitting semiconductor laser that oscillates the single-mode laser with favorable performance is constructed.