A circuit incorporated IGBT is provided with a semiconductor substrate having an IGBT area and a circuit area which are adjacent to each other. In a semiconductor layer of one conductivity type in which a circuit element is formed in the circuit area, there is provided another semiconductor layer of another conductivity type which adjoins the circuit element and has an impurity concentration higher than that of the semiconductor layer of the one conductivity type. An electrode contacts the other semiconductor layer and is connected to an electrode of the IGBT. Carriers are ejected from the other semiconductor layer to the electrode of the IGBT, thereby making it possible to prevent an erroneous operation of the circuit.