PURPOSE: To provide a high-reliability high potential part installed power supply which is made small, whose economical efficiency is enhanced and which has simplified a control circuit and a protective circuit.

CONSTITUTION: In a plurality of high potential part installed power supplies for a neutral-particle impinging apparatus, a DC output which has rectified an alternating current supplied from an AC bus is supplied to an ton source as a load. In the high potential part installed power supplies, circuits for high potential parts are insulated collectively by a step-down transformer 13 connected to the AC bus 1, and all or every function of the circuits for the high potential parts are installed on the same insulating stand.