To enhance the stability of, and responsiveness to, set temperature for high-quality products by using the control of coolant flow rate and the control of the amount of heat from a heating source to control the temperature of wafers.

During processing with the title temperature control device, a wafer 10 is cooled by coolant passing through a piping 11 with a lower electrode 3 in-between, and further the wafer 10 is heated by a ceramic heater 7 with the lower electrode 3 in-between so that the temperature of the wafer 10 will not be excessively lowered. A controller 12, fed with the temperature of the wafer 10 from an optical fiber thermometer 6, controls the flow rate of the coolant and the amount of heat from the ceramic heater 7 to keep the wafer at a set temperature with stability. Since the control of the flow rate of the coolant and the control of the amount of heat from the heating source are used to control the temperature of wafers, as mentioned above, it is possible to swiftly bring a wafer at the set temperature and to keep the wafer at the set temperature with stability.