A cooling device configured to perform cooling through use of a coolant, comprising: a compressor configured to compress the coolant; a first heat exchanger configured to perform heat exchange between the coolant having been compressed and outside air; a first gas-liquid separating unit configured to separate the coolant having been subjected to the heat exchange by the first heat exchanger into gas and liquid; a decompressor configured to decompress the coolant from the first gas-liquid separating unit; a second heat exchanger configured to perform heat exchange between the coolant having been decompressed and air-conditioning air; a second gas-liquid separating unit configured to separate the coolant having been subjected to the heat exchange by the second heat exchanger into gas and liquid, and supply the coolant to the compressor; a switch valve (270, 400) configured to switch the first gas-liquid separating unit and the second gas-liquid separating unit into a communicating state to perform coolant transfer of a liquid-phase component from the second gas-liquid separating unit to the first gas-liquid separating unit, the coolant transfer being started when the compressor is at a stop; and a pressure regulating unit (350, 350A) coupled to the first gas-liquid separating unit and the second gas-liquid separating unit and configured to adjust a pressure difference between the first gas-liquid separating unit and the second gas-liquid separating unit; and a control device, the second gas-liquid separating unit being arranged at a position relatively higher than the first gas-liquid separating unit, characterized in that the control device causes the pressure regulating unit (350, 350A) to hold the pressure difference between the first gas-liquid separating unit and the second gas-liquid separating unit before starting the coolant transfer, and the control device controls the pressure regulating (350,350A) after the coolant transfer is terminated such that the pressure difference between the first gas-liquid separating unit and the second gas-liquid separating unit approaches the reference pressure difference having been held. a compressor configured to compress the coolant; a first heat exchanger configured to perform heat exchange between the coolant having been compressed and outside air; a first gas-liquid separating unit configured to separate the coolant having been subjected to the heat exchange by the first heat exchanger into gas and liquid; a decompressor configured to decompress the coolant from the first gas-liquid separating unit; a second heat exchanger configured to perform heat exchange between the coolant having been decompressed and air-conditioning air; a second gas-liquid separating unit configured to separate the coolant having been subjected to the heat exchange by the second heat exchanger into gas and liquid, and supply the coolant to the compressor; a switch valve (270, 400) configured to switch the first gas-liquid separating unit and the second gas-liquid separating unit into a communicating state to perform coolant transfer of a liquid-phase component from the second gas-liquid separating unit to the first gas-liquid separating unit, the coolant transfer being started when the compressor is at a stop; and a pressure regulating unit (350, 350A) coupled to the first gas-liquid separating unit and the second gas-liquid separating unit and configured to adjust a pressure difference between the first gas-liquid separating unit and the second gas-liquid separating unit; and