The present invention provides a temperature control unit for an electrostatic adsorption electrode that is capable of controlling the wafer temperature rapidly over a wide temperature range without affecting in-plane uniformity while high heat input etching is conducted with high wafer bias power applied. A refrigerant flow path provided in the electrostatic adsorption electrode serves as an evaporator. The refrigerant flow path is connected to a compressor, a condenser, and a first expansion valve to form a direct expansion type refrigeration cycle. A second expansion valve is installed between the electrostatic adsorption electrode and the compressor to adjust the flow rate of a refrigerant. This makes it possible to compress the refrigerant in the refrigerant flow path of the electrostatic adsorption electrode and adjust the wafer temperature to a high level by raising the refrigerant evaporation temperature. Further, a thin-walled cylindrical refrigerant flow path is employed so that the thin-walled cylinder is deformed only slightly by the refrigerant pressure.