PURPOSE: To execute safely and easily a maintenance operation such as a check at a height of a cooling tower, a repair of broken spot of an outer wall part or washing of a filler by a method wherein guide beams are fitted to the outside peripheral wall of the cooling tower and a ladder to which engaging parts to be hooked on the guide beams are attached is fitted movably in the horizontal direction of the cooling tower.

CONSTITUTION: Guide beams 3 are attached respectively in the horizontal direction between the outside peripheral wall 11 of an upper unit 11-1 of a cooling tower 1 and the outside peripheral wall 11 of a middle unit 11-2 thereof and between the outside peripheral wall 11 of the middle unit 11-2 and the outside peripheral wall 11 of a lower unit 11-3, and a ladder 2 is engaged with and fitted to the guide beams 3 and is made movable in the horizontal direction. The ladder 2 is fitted slidably in the horizontal directions X-1 and X-2 of the cooling tower 1 by engaging parts 24 fitted to the guide beams 3 of the cooling tower 1. In regard to the ladder 2, the engaging parts 24 are attached, with arms 23 interposed, to handrails 25 provided on the outside peripheral wall 11 side of the cooling tower 1, while steps 22 and safety recliners 21 are provided integrally respectively.