PURPOSE: To mount and dismount samples in a short time by providing a sample conveying arm between an etching chamber and a spare chamber for exchanging samples, making it rotatable 180° and performing mounting and dismounting of the sample simultaneously in a plasma etching device.

CONSTITUTION: A conveying arm 8 is provided between an etching chamber 1 in which a reaction tube 6a provided with a microwave generator 6 projects and a spare chamber 2 for sample exchanging adjacent thereto, and support members 9 containing a sample 18 to be etched are mounted to both ends thereof. A gate valve 3 is provided between the etching chamber 1 and the spare chamber 2 to provide such width at which the arm 8 can pass freely when the valve is opened. The arm 8 receiving the sample 18 from a load cassette 15a in the chamber 2 rotates 180°, and places the sample on the sample rotary table 4 in the chamber 1 by the supporting member 9 on the opposite side. The sample is plasma etched under the reaction tube 6a. The mounting and dismounting operations of the sample can be 1/2 that in the prior art and the etching operation is carried out in a short time.