A driver circuit for turning ON and OFF one of two parallel-connected insulated-gate semiconductor elements includes a voltage control circuit that controls a level of a power supply voltage in response to a detected element temperature of the one semiconductor element, a constant current supply section, responsive to a drive signal, for supplying a constant current to a gate of the one semiconductor element to turn the one semiconductor element ON, the power supply voltage being supplied to the constant current supply section from the voltage control circuit, and a discharge circuit, responsive to the drive signal, for discharging an electric charge accumulated in the gate to turn the one semiconductor element OFF.