A surge voltage target setting unit obtains a main circuit power supply voltage of a semiconductor power conversion device based on an inter-terminal voltage of a semiconductor switching element detected by a voltage detection unit, and sets a control target of a surge voltage in accordance with the obtained main circuit power supply voltage. An active gate control unit, when the semiconductor switching element is turned off, sets a quantity of voltage modification so as to modify a gate voltage in a direction raising the gate voltage, that is, in a direction lowering a turn-off speed, based on feedback of the inter-terminal voltage, when the inter-terminal voltage exceeds the control target.