A light source apparatus includes: a light-emitting unit which includes a plurality of emission areas emitting light periodically at different phases and in which at least two light sources are disposed in each emission area; a detection unit configured to detect light from the light-emitting unit; and a control unit configured to select the plurality of light sources sequentially and to perform lighting-control of temporarily reducing emission brightness of light sources other than the selected light source, wherein the control unit selects lighting-control target light sources so that lighting-control is sequentially performed on light sources disposed in different emission areas among the plurality of emission areas.