The present invention provides a safe circuit that can prevent an arm short, when a half-bridge circuit is configured by using a normally-on switching element, and the half-bridge circuit is used as a driver circuit or an inverter circuit. In a driver circuit configured by a half-bridge circuit in which one of input and output terminals of a first switching element 14 is connected to a first power-supply voltage V1 on a high-voltage side, and the first switching element 14 and a second switching element 15 are connected in series, a normally-off third switching element 16 is inserted between the second switching element 15 and a second power-supply voltage V2 on a low voltage side. The third switching element 16 is turned off, when an operating voltage VH or VL supplied from control-circuit power supplies 13a and 13b is insufficient for the operation of a control circuit 11.