A light source apparatus according to the present invention includes a circuit board; a light source mounted on the circuit board; a first temperature measurement element that measures an ambient temperature of the circuit board and outputs a first signal that represents the measured result; a second temperature measurement element that measures a temperature of the circuit board and outputs a second signal that represents the measured result; and a light source drive control section that controls driving of the light source. The light source drive control section does not drive the light source if the temperature represented by the second signal is lower than the temperature represented by the first signal.