PURPOSE: To completely cancel the dispersion of plasma intensity in the diametral direction of a sample base by turning a sample while dry-etching the sample, rotating the sample further centering around eccentric from the center of the sample.

CONSTITUTION: An electrode 2 as an anode is fitted to an upper section in a reaction chamber 1 for etching, and a rotary table 3 is mounted rotatably just under the electrode 2. A plurality of sample bases (combining electrodes as cathodes) 5, 5... to which samples 4 are supported separately are each set up rotatably at the position being eccentric from the shaft 3a of the rotary table 3, a motor 6 is directly coupled with the shaft 3a of the rotary table 3, and motors 7, 7... individually rotating and driving respective sample base 5 are fitted to the rotary table 3. Since each sample base 5 is sun-and-planet moved under the anode 2 in the etching reaction chamber 1, the dispersion of plasma intensity in the radial direction of respective sample 4 is compensated with the motion of the samples, thus equalizing etching on the surfaces of the samples 4.