To effect heat exchange between brine and circulation air efficiently.

Circulation air is conducted through a cold air duct 12 to flow from the lower part toward the upper part of the same by a fan 16. Brine, cooled by an evaporator 4, is discharged from a brine discharging device 11, provided at the uppermost part of the cold air duct 12, into the cold air duct 12 whereby heat exchange between the brine and the circulation air is effected directly to cool the circulation air. Air, cooled in such a manner, is discharged out of a cold air discharging port 20 to flow through a commodity receiving unit 21 and cool the commodity. On the other hand, a temperature sensor 24 is provided in the circulation passage of the circulation air to control a discharging amount control valve 9 based on the output of the sensor 24 whereby the amount of discharging brine is changed to control a temperature. Further, a concentration sensor 28 is provided in a brine recovering pipe 27 and when the output of the sensor 28 has become not more than a predetermined value, the brine of a high concentration, which is stored in a brine tank 6, is supplied from a sub tank 29 to regulate the concentration of the brine.