PURPOSE: To prevent generation of electric field concentration, and obtain excellent uniformity of film thickness, by using a susceptor having a recessed part wherein the inner diameter is larger than the diameter of a substrate to be mounted and the surface is circular, and by mounting a substrate in the recessed part.

CONSTITUTION: A recessed part 27 is formed inside a susceptor 22 of a lower electrode 20. The inner diameter of the recessed part 27 is a little larger than the diameter of a substrate 6. Since the substrate is nearly disklike, the recessed part is molded circular. The depth of the recessed part 27 is equal to, or preferably, a little larger than the thickness of a substrate to be mounted in the recessed part 27. When the depth of the recessed part 27 is less than the thickness of the substrate 6, the distance from a heater cover 23 becomes small, so that an electric field is apt to concentrate, which is not desirable. The susceptor 22 is so assembled that a heater cover 23 covers a part of the upper surface of the outer periphery of the susceptor 22. A part of the heater cover is stacked on the susceptor, in order to relieve electric field concentration, make gas flow uniform, and form a film having uniform thickness distribution.