To prevent the generation of element destruction without deviating from a safe operation area at the time of the overcurrent at the time of adding a sense IGBT(insulated gate bipolar transistor) to a main IGBT chip and equivalently detecting the collector current of the main IGBT from a sense current.

By connecting an MOSFETT1 between the emitter Es of the sense IGBT and the emitter E of the main IGBT and using it as a variable sense resistor, regardless of the size of the collector emitter voltage of the main IGBT, the collector current of the main IGBT is limitd to an almost fixed value. In such a manner, even for a normal IGBT without a built-in sense IGBT, overcurrent protection is performed.