An AC power supply device of the invention includes: a DC power supply unit that outputs a DC voltage; an inverter unit that includes at least four bridge-connected switching elements, a pair of input terminals connected to the DC power supply unit, and an output terminal group connected to an external load, and that converts the DC voltage, which is input to the pair of input terminals from the DC power supply unit, into a single-phase or three-phase AC voltage, and outputs the single-phase or three-phase AC voltage to the external load from the output terminal group; a switching control unit that controls the opening/closing of the switching elements; and an efficiency improvement coil that is connected between terminals of the output terminal group and is connected in parallel to the external load. Accordingly, it is possible to reduce a switching loss, which is generated when a switching operation is performed, by a simple circuit configuration and to achieve the reduction of the size and weight of the de
