When a short-circuit failure has occurred in a power semiconductor device provided in a power module, a radical and rapid temperature increase is prevented by instantly interrupting a short-circuit current. A power module 10 has a package 10a. Provided in the package 10a are: a MOSFET 21 serving as the power semiconductor device; a resistor 23 serving as a detecting means for detecting an operation state of the MOSFET 21 and outputting a detection signal; and a MOSFET 22 serving as a current-interrupting purpose switch connected in series to the MOSFET 21. In response to a control signal Si2 generated on the basis of the detection signal, the MOSFET 22 goes into a conduction state during a normal operation of the MOSFET 21 and goes into an interruption state so as to interrupt a current flowing in the MOSFET 21 when a short-circuit failure has occurred in the MOSFET 21.