A temperature control apparatus including a temperature control head kept in contact with an electronic device as a testing object thermally, an electric heater attached to the temperature control head, a refrigerant passage formed within the temperature control head so as to run through inside thereof, a compressor which compresses refrigerant coming out of the temperature control head, a temperature sensor which detects a temperature of refrigerant on an outlet side of the compressor, a condenser which condenses refrigerant coming out of the compressor, a returning portion which returns refrigerant condensed by the condenser to the temperature control head, and a control portion which bypasses the condensed refrigerant to the intake side of the compressor by a predetermined quantity corresponding to an output of the temperature sensor.