Abstract: There is provided an environmental test apparatus that can create a predetermined environment inside a test chamber, the environmental test apparatus including: the test chamber for placing a test target object; a heating portion; and a cooling portion. The cooling portion has a refrigeration circuit having a compressor, a condenser, an expansion portion, and an evaporator and in which a phase-changing refrigerant is to be circulated. The refrigeration circuit has a first bypass flow path connecting a discharge side of the condenser and a suction side of the compressor and the first bypass flow path is provided with a first flow rate control portion. A temperature measurement portion for measuring a temperature of the compressor and a controller are provided. The controller is configured to control a substantial degree of opening of the first flow rate control portion according to a detection value of the temperature measurement portion.