PURPOSE: To prevent the contamination of samples with falling of adhered particles by collecting the splashing particles and forming the rough surface of Al or Mo coated on the internal surfaces of a vacuum vessel and the specified external surface of the internal component.

CONSTITUTION: An electrode 8 holds a target in a vacuum vessel 1, a sample is put on a sample stand 5. After pressure reducing and discharge of the target from an air discharge spot 11, gas is induced from a gas inducing spot 10 to control under the specified pressure. Thereafter, the electrical discharge is carried out by adding voltage to each coil 7, electrode 8 and anode 3, and particles discharged from the target is adhered on the sample for forming a film. At this time, on the internal surface of an anode 3, shutter 4, sample stand 5, where the particles splash, Al or Mo 6 is coated by flame coating to be ≥200μm at roughness of their surfaces for collecting the particles, preventing their falling and also preventing the contamination of the samples by dropping foreign matters.