PURPOSE:To make it possible to control the voltage to be applied to an acceleration electrode with a voltage lower than the voltage applied to the acceleration electrode, by controlling a converter and a high-frequency inverter so as to regulate the output voltage. CONSTITUTION:Converters 10, 20A, and 20B to convert an AC power into a DC power, high-frequency inverters 11, 21A, and 21B to convert the DC power to a DC power of the high-frequency higher than that of the converters, high-frequency transformers 12, 22A, and 22B to raise the output voltage of the high-frequency inverters, and, high-frequency converters 13, 23A, and 23B to convert the AC power into a high voltage of DC power are provided. As a result, the output voltage in each phase can be controlled with a low voltage, and a smoothed AC voltage can be applied to each acceleration electrode. Consequently, each DC power source can be controlled by a voltage lower than the voltage to be applied to each acceleration electrode, and the loss of the total power sources can be reduced.