PURPOSE:To improve the cooling efficiency of a fish hold by providing a sprinkler pipe which is connected to a chilled water introducing pipe and jetting out chilled water while preventing fish from being splashed with the water. CONSTITUTION:One sea water inlet hole is for feeding liquid cooled sea water to be stored in a body case 11, while one end of the other inlet hole 16 is opened to a mating face 27 with a case cover 12. A water introducing hole 28 provided on the case cover 12 is connected to a sprinkler pipe 29, on which a number of water jet out ports 30 are opened. Thereby, a proper quantity of chilled water is jetted out of the sprinkler pipe 29 in a condition that fish is prevented from being splashed with the water in a fish hold 45 in which fish is loaded, to effectively keep the atmosphere in the fish hold at a proper cooling temp. And, air in the fish hold 45 is cooled nearly to the freezing point through the heat exchanger of a heat pump and kept cooled due to the spraying of sea water. Thereby, the fish hold 45 is made an air cooled system enabling fish housing cases 21 to be piled.
