Vacuum processing apparatus and plasma processing apparatus with temperature control function for wafer stage

A plasma processing apparatus includes a processing chamber, a wafer table, a refrigerant passage disposed inside the wafer table in which a refrigerant flows, a refrigeration cycle comprising the refrigerant passage in the wafer table as a first evaporator in which the refrigerant is evaporated as a result of a heat-exchange therein, a compressor, a condenser and an expansion valve, a second evaporator, and a controlling unit which adjusts a number of rotations of the compressor based upon a degree of dryness of the refrigerant at a position on the refrigeration cycle after passing through the first evaporation in a range in which dry-out does not occur in the first evaporator, and the dryness of the refrigerant being determined based upon an amount of a heat exchange during the evaporation of the refrigerant in the second evaporator.