PURPOSE: To jet a compressed fluid to the surface of a structure for obtaining a sufficient cleaning effect by providing a rotary nozzle body provided in a cleaner body with a cleaner nozzle port and a hose for supplying the compressed fluid to the rotary nozzle body.

CONSTITUTION: A cleaner 1 is composed of a press frame 10 for pressing the cleaner 1 against a dam bank body, a cleaner body having the frame 10 and a support frame 20 provided with a rotary nozzle body 21, a rotary nozzle body 21 provided on a rotary shaft 24 mounted on the support frame 20 and having a cleaning nozzle port 22, rotary nozzle ports 23a, 23b and a fluid supply port for supplying cleaning liquid containing a detergent as the compressed fluid from an external compression pump to the rotary nozzle body 21. The cleaner 1 is hung down from the top of the dam band by a lift means like a truck crane to jet the cleaning liquid supplied from a fluid supply hose 30 toward the surface 41 of the dam bank body from the cleaning nozzle port 22 of the rotary nozzle body 21 and clean stains like a moss deposited on the surface 41 of the dam bank body along the nealy strip-like cleaning track.