To enable an environmental test device 10 which comprises a cooling heat exchanger 22 for cooling and dehumidifying air, a heater 23 for heating air, and a humidifier 21 for humidifying air and controls the temperature and humidity of air in a test chamber C1 to a target temperature and a humidity to save energy while in steady operation in which control amounts are small.

An environmental test device comprises an evaporator in a cooling circuit as a main cooling heat exchanger 31 and is provided with an auxiliary cooling heat exchanger 32 of which heat capacity is smaller than that of the main cooling heat exchanger 31, with the auxiliary cooling heat exchanger 32 being constituted of an electronic cooler 33 such as a Peltier effect element.