PURPOSE: To perform dust collection at high efficiencies under high vacuum by providing near a transfer section in a vacuum chamber a dust collecting electrode for applying positive D.C. high voltage not so high enough as to cause an electric discharge and also providing a source of electron beam for applying electron beams through the space near the surface of the dust collecting electrode.

CONSTITUTION: Near a transfer section 2 in a vacuum chamber of a vacuum treatment device wherein such a treatment as membrane accumulation, etching, surface cleaning, etc., is applied to the surface of a substrate 5 under vacuum, a dust collecting electrode 31 for applying a high positive D.C. voltage, which is not so high as to cause an electric discharge, is provided, while a source 21 of electron beam which applies electron beam through the space near the surface of the dust collecting electrode 31 is provided. As a result, by the addition of a simple device, dust collection can be conducted at high efficiencies under vacuum, practically without exerting any influence on the transfer of the substrate.