PURPOSE: To reduce a switching loss by a method wherein a series inductance which suppresses the rise of the discharge current of a snubber capacitor is contained in a discharge resistor arm.

CONSTITUTION: A feedback diode 2 is connected in reverse-parallel with a semiconductor switching device 1. An individual RCD charge/discharge type snubber circuit 13 is also connected in parallel with the semiconductor switching device 1. The snubber circuit 13 is composed of a series arm composed of a snubber capacitor 4 and a snubber diode 5 and a discharge resistor am 18 which is connected in parallel with the snubber diode 5. A winding type discharge resistor 17 is employed in the discharge resistor arm 18. The speed of the change of a discharge current Ic created when the switching device 1 is turned on can be suppressed to be a required value by the resistance component R and the inductance component L of the winding type discharge resistor 17. With this constitution, a switching loss can be reduced.