PURPOSE: To provide a semiconductor device provided with an overheat protecting function which does not perform malfunction by high positive dv/dt generated at the time of the reverse recovery of an FWD.

CONSTITUTION: This semiconductor device is composed of an intelligent power module for which the parallel circuit of an IGBT 3 and the FWD 4 is bridge- connected and an IC 16 for control mounted with the driving circuit of the lower side arm 2 is provided with an overcurrent protection circuit for detecting the overcurrent of the IGBT 3 by the detection resistor 7 and an overheat protection circuit for detecting the overheat of the IGBT 3 by a thermistor 8. As a serge voltage suppression means for suppressing a serge voltage generated at the common output terminal A/E of alarm signals by the high positive dv/dt generated at the time of the reverse recovery of the FWD 4, a unidirectional yield diode (Schottky diode) 20 with low forward voltage decline connected between terminals with a direction from the common output terminal A/E of the alarm signals towards the input terminal Vcc of a control power source 21 as a forward direction is provided for instance.