To provide a cooling device, contracted in the area of installation and reduced in a manufacturing cost as well as power consumption.

The inside of a blast chiller 2 is cooled by supplying refrigerant, cooling brine in a brine chiller unit 4, into the cooler 21 of a blast chiller 2. The brine, cooled in the brine chiller unit 4, is supplied into an ice heat storage tank 23 at night by switching a three-way switching valve 17, while the same brine is supplied into a cold trap 7 in daytime. According to this method, ice making and the storage of cold water are effected in the ice heat storage tank 23 at night, whereby a tumble chiller 3 is cooled by the cold water, stored in the ice heat storage tank 23, in daytime. Accordingly, a vacuum cooler 1, the blast chiller 2 and the tumble chiller 3 or three sets of coolers can be operated by only one set of brine chiller unit 4 in daytime.