PURPOSE: To efficiently remove sulfuric products from an exhaust pipe of the high vacuum exhaust system in an etcher which conducts dry etching accompanied by deposition of sulfuric products.

CONSTITUTION: In the high vacuum exhaust system of a magnetic field microwave plasma etcher 1, at least a part of an exhaust pipe 6 which connects a turbomolecular pump 5 and a rough drawing pump 7 is provided with a heating mechanism H or a cooling mechanism C. The heating mechanism consists of heating means such as a heater and a thermostat, and this part is heated up to a temperature higher than the sublimation temperature or the decomposition temperature of a sulfuric product to prevent its deposition. The sulfuric product is finally trapped by a desulfuration mechanism 9. In the case of providing the cooling mechanism C, the exhaust pipe 6 is made attachable and detachable, and a refrigerant jacket is provided by surrounding it, where sulfuric products are deposited. Cleaning is conducted by removing the exhaust pipe 6.