A transistor (2) is provided on a semiconductor substrate (8). A temperature detection diode (4) for monitoring the temperature on the upper surface of the semiconductor substrate (8) is provided on the semiconductor substrate (8). An external electrode (7) is connected in common to an emitter (E) of the transistor (2) and a cathode (K) of the temperature detection diode (4). It is thereby possible to omit an external electrode for the cathode (K) of the temperature detection diode (4), making it possible to reduce the size of the device and improve the assembling properties.
