PURPOSE: To facilitate the maintenance of a cooling apparatus, by a method wherein air for cooling water is introduced into a cooling tower and is discharged therefrom by an ejector fan having no movable part.

CONSTITUTION: At a nozzle part 52 for an ejector fan 48, compressed air for drive is supplied to a ringed way from an intake 56, through a compressed air-supplying pipe line 58. The compressed air is injected into a flow way 61 in a bugle-like tube 54 for converting dynamic pressure, through a nozzle and is discharged together with the air in the flow way 61 toward the outside of a cooling tower 10 from the top end of the bugle-like tube 54. In such a way, since air 60 in the cooling tower 10 is discharged by the ejector fan 48 having no movable part, a cooling apparatus is hardly damaged and can be easily maintained.