A gate drive apparatus which is connected to a gate of a switching device of voltage drive type, and which outputs to the gate, gate signals that turn ON/OFF the switching device on the basis of ON/OFF gate control signals; - a gate drive apparatus for either or both of the turn-ON operation and the turn-OFF operation, comprising: - a constant-current-pulse gate drive circuit which creates the gate signal as a constant-current output, - a constant-voltage-pulse gate drive circuit which creates the gate signal as a constant-voltage output, and - a decision switch circuit which switches between the operation of the constant-current-pulse gate drive circuit and the operation of the constant-voltage-pulse gate drive circuit for driving the gate of the switching device, characterised in that the decision switch circuit comprises - a gate voltage detection circuit which detects a voltage of the gate, - a first decision circuit which decides magnitudes of the gate voltage and a predetermined first set value, - a second decision circuit which decides magnitudes of the gate voltage and a predetermined second set value, and - a switch circuit which, in the turn-ON operation, first connects the constant-current-pulse gate drive circuit to the gate and subsequently connects the constant-voltage-pulse gate drive circuit to the gate instead of the constant-current-pulse gate drive circuit when it has been decided by the first decision circuit that the gate voltage exceeds the first set value, and which, in the turn-OFF operation, first connects the constant-current-pulse gate drive circuit to the gate and subsequently connects the constant-voltage-pulse gate drive circuit to the gate instead of the constant-current-pulse gate drive circuit when it has been decided by the second decision circuit that the gate voltage is less than the second set value. - a gate drive apparatus for either or both of the turn-ON operation and the turn-OFF operation, comprising: - a constant-current-pulse gate drive circuit which creates the gate signal as a constant-current output, - a constant-voltage-pulse gate drive circuit which creates the gate signal as a constant-voltage output, and - a decision switch circuit which switches between the operation of the constant-current-pulse gate drive circuit and the operation of the constant-voltage-pulse gate drive circuit for driving the gate of the switching device, characterised in that the decision switch circuit comprises - a gate voltage detection circuit which detects a voltage of the gate, - a first decision circuit which decides magnitudes of the gate voltage and a predetermined first set value, - a second decision circuit which decides magnitudes of the gate voltage and a predetermined second set value, and - a switch circuit which, in the turn-ON operation, first connects the constant-current-pulse gate drive circuit to the gate and subsequently connects the constant-voltage-pulse gate drive circuit to the gate instead of the constant-current-pulse gate drive circuit when it has been decided by the first decision circuit that the gate voltage exceeds the first set value, and which, in the turn-OFF operation, first connects the constant-current-pulse gate drive circuit to the gate and subsequently connects the constant-voltage-pulse gate drive circuit to the gate instead of the constant-current-pulse gate drive circuit when it has been decided by the second decision circuit that the gate voltage is less than the second set value.