PURPOSE: To blow out the cool air or the warm air of an air-conditioning system into a broad scope in a cage and to prevent the uneven air-conditioning in the cage by providing a blowout nozzle adapter at the tip of the exhaust duct of the air-conditioning system.

CONSTITUTION: At the tip of an air exhaust duct 7, a blowout nozzle adapter 10 which consists of a grille 10a and flow regulating plates 10b is provided. As a result, the cool air or the warm air from an air-conditioning system 3 is blown out not only to the floor surface direction, but also to the side direction. Consequently, the scope of blowoff is expanded, and generating an uneven air-conditioning to concentrate the cool air or the warm air to one part in the cage can be suppressed.