A light source apparatus includes a semiconductor light-emitting device, a cooling device configured to be able to cool the semiconductor light-emitting device, a light-emitting device drive section that supplies a light-emitting device drive signal to the semiconductor light-emitting device, a cooling device drive section that supplies a cooling device drive signal to the cooling device, a light-emitting device drive control section that sets a duty ratio of the light-emitting device drive signal and controls an amount of light emission of the semiconductor light-emitting device, a temperature sensor that measures a temperature of the semiconductor light-emitting device, and a cooling device drive control section that controls the cooling device drive section so as to generate the cooling device drive signal having a same duty ratio as the duty ratio of the light-emitting device drive signal set by the light-emitting device drive control section and having timing synchronized with the light-emitting device drive signal and controls the cooling device drive section so as to adjust a signal level of the cooling device drive signal based on a measurement result of the temperature sensor.
