A driver circuit includes: a variable power supply configured to apply a power supply voltage to a light emitting device and to vary a voltage value of the power supply voltage; a current-control switching device electrically connected to the light emitting device and configured to control a current flowing in the light emitting device; a detection part configured to detect a current value and a voltage value related to the current flowing in the light emitting device; and a control part configured to determine a minimum voltage of the power supply voltage based on a detection result of the detection part.