To provide a semiconductor device which can improve its operation reliability and also to provide a power conversion device which uses the semiconductor device.

This device uses an overcurrent protection circuit 20 and a short circuit current protection circuit 21 as the self-protection means which are related to the current elements flowing an IGBT element 17. When these circuits 20 and 21 operate, the gate control signal which is supplied to the element 17 from a gate drive circuit 25 is stopped for execution of the protecting operations and also an actuating signal is supplied to a self-holding circuit 27. The circuit 27 holds the protecting operations of the self-protection means until the circuit 27 is reset by the input signal of a reset signal terminal 272 and also applies a signal to the circuit 25 during a self-holding period.