A gate drive circuit includes a power supply circuit that has an output switch function for switching a voltage value of a drive voltage between two levels, a gate-ON drive circuit that outputs a constant electric current toward a gate of an IGBT from an output terminal of the power supply circuit, and a control section performs a constant electric current drive of a gate of the IGBT at a time of a turn-ON by operating the gate-ON drive circuit. At a turn-ON start time, the control section sets the drive voltage to a relatively-high first set value, and then switches the drive voltage to a relatively-low second set value at a switch timing after a mirror period end time.