Abstract: A water delivering tube having a spray nozzle secured to the front side thereof is detachably disposed in front of a blower so as to eject water therefrom in the form of mist particles. To feed pressurized water to the water delivering tube, a water feeding tube is connected to the water delivering tube. As the blower is rotated, an environmental air is introduced into the interior of a building to be cooled, and subsequently, it is mixed with the mist particles which in turn are vaporized by the latent heat of the mist particles appearing as the foregoing vaporization proceeds. Thus, a large quantity of warm air in the environmental air in the interior of the building can quickly be cooled without any necessity for carrying out heat exchanging.