It has been found that an organic component is emitted from a member such as a crucible or a gasket constituting an apparatus for vacuum treatment and an element is contaminated with said organic component emitted, and, as a result, members of the apparatus for vacuum treatment are subjected to a treatment for reducing the emission of an organic component. For example, a crucible is made from a material having a reduced catalytic activity to a material for use in the vapor deposition in question and a gasket is used after a treatment for reducing the bleeding of an organic component or is made from a material containing a reduced amount of an organic component.