When there is a short circuit failure between the gate and emitter of a main switching element such as an IGBT, the temperature of a turn-on gate resistor or turn-off gate resistor is detected by a thermistor, and a drive circuit is protected by turning off a turn-on gate drive switching element or a turn-off gate drive switching element. Furthermore, instead of detecting the temperature of the turn-on gate resistor or turn-off gate resistor, a thermistor is connected in series with the turn-on gate drive switching element or turn-off gate drive switching element, the resistance change corresponding to a change in temperature of the thermistor is detected, and the drive circuit is protected by turning off the turn-on gate drive switching element or turn-off gate drive switching element.