PURPOSE: To sufficiently control an energy of ions in the plasma with a DC voltage of acceleration power supply and leads the sufficient amount of ions of adequate energy to the target by inserting insulated transformer between a matching circuit and an electrode.

CONSTITUTION: An insulated transformer 11 where the primary side and the secondary side are insulated is inserted between an output end of a matching circuit 8 and a terminal of a high frequency coil 7. For example, a chamber 1 to be exhausted is exhausted, the Ar gas is supplied to said chamber, and the chamber 1 to be exhausted is filled with the plasma ambient by applying a high frequency voltage from a high frequency power supply 9. Where an evaporating material in a crucible 3 is vaporized by the electron beam impact under this condition, the vaporized particles are ionized and ion energy is activated by a DC voltage of acceleration power supply 10 and the ions are adhered to the target 2. Since a high frequency voltage to be applied to the high frequency coil 7 from the insulated transformer 11 is a floating voltage, a potential for the earth of plasma formed around the high frequency coil 7 is positive, the ion in the plasma is energized by a negative DC voltage applied to the target 2, and such ions are running to the target 2.