PURPOSE: To increase the cooling efficiency of the titled device by a method wherein an air passage, a part of which is linked to an aperture section, is provided at the upper ventilating hole located on the ceiling part of a cubicle, and a plurality of air blast holes are provided on the underside part and/or the side face part of said air passage, thereby enabling to reduce temperature difference by performing the cooling operation uniformly.

CONSTITUTION: An air passage 14, a part of the opening thereof is connected to an upper ventilating hole 8, is provided on the ceiling part of a cubicle, thereby enabling to let in the cooling air 13 from a blower 9 and flow into said air passage 14. On the underside part of the air passage 14, an air blast hole 15 is provided. An air duct 16 having a square cross section is used for the air passage, and an air blast hole 15 is provided on the underside part of the air duct. When the cubicle has a wide lateral width and the air blast hole 15 is provided at the side face part 16a, cooling efficiency can be increased. The warmed up air in the cubicle 1 is sucked into the lower air hole 8b, cooled by an air cooler 10, changed into cooled air 13, sent to the air passage 14 by a blower 9, and the cooleld air is sent out from an air blast hole 15 in a uniformly dispersed state.