PURPOSE: To handle the abnormality of a vapor deposition source without breaking the vacuum of a sample chamber and to improve the yield of production by providing respectively independent leak valves and rough evacuating valves to the sample chamber and vapor deposition source chamber.

CONSTITUTION: A sample 4 of a substrate is set in the sample chamber 1 and a main valve 7 is shut, then a sepn. valve 5 is opened. After a rotary pump 10 is operated, an auxiliary valve 11 is opened and a diffusion pump 9 is operated. The rough evacuating valve 12A or 12B is opened to open the inside of the sample chamber 1 and the vapor deposition source chamber 2. The valve 7 is then opened to evacuate the inside of the chamber 2 to the prescribed high vacuum. A shutter 13 is opened to strike the metallic vapor from the vapor deposition source 14 against the sample 4, thus forming a thin metallic film. The valve 5 and the valve 7 are shut and the leak valve 15B is opened to restore the atmospheric pressure in the chamber 2 when the abnormality arises in the source 14. The remedy for the abnormality is then taken.