To eliminate a pressure difference between a high-pressure compressor side and a low-pressure evaporator side by bringing an opened condition to preclude a compressor from being applied with an excessive load, when a temperature is elevated in a storage chamber to come near to an operation start temperature of the compressor, and to control cooling energy from being consumed wastefully.

In this cooling device 10 provided with a cooling circuit comprising the evaporator 2 provided inside the storage chamber 1, the compressor 3 outside the chamber, a condenser 4, a solenoid valve 15, and a capillary copper pipe 16 inside the chamber, the solenoid valve 15 is opened when the temperature is elevated in the storage chamber 1 to come near to the operation start temperature of the compressor 3, and the compressor 3 is started up at the point when 10 seconds lapse away counted from the time point of the opening thereof. That is, the compressor 3 is started up after the pressure difference between high pressure in the compressor 3 side and pressure in the evaporator 2 side is eliminated. A small-sized DC motor capable of controlling its rotational speed is used as a driving source for an in-chamber fan 8, and the rotational speed is reduced to about 60% when the compressor 3 is stopped.