An output of a gate driver that drives a main switch is connected to the gate of the main switch, and a low-voltage side power supply terminal of the gate driver is connected to a source of the main switch via a current limiting resistor. Moreover, a suppression capacitor for suppressing rapid changes in current, having a prescribed capacitance, is connected between the drain of the main switch of a main circuit and the low-voltage side power supply terminal of the gate driver. This makes it possible to suppress the rapid change in current that occurs when the main switch switches OFF as well as to prevent extremely large currents from occurring in a low-voltage side power supply line of the driver circuit.