To improve a drawback that ice blocks in an ice storage water tank being sprayed from the water spray tube of a wet air cleaning flower showcase melt away in a relatively short time.

An ice storage water tank 4 and a water receiving tank 5 are disposed under the floor in a compartment and a duct 6 provided with a water spray tube 7 is disposed above the water receiving tank 5. Freezing water in the ice storage water tank 4 and water in the water receiving tank 5 are mixed and fed to the water spray tube 7 provided in the duct 6. Air in the compartment is then circulated upward through the duct 6 being sprayed with the cooling water thus cooling the compartment. After cooling the air in the compartment, warmed spray water is fed directly into the ice storage water tank 4 so that the water temperature is not increased thus preventing ice blocks in the ice storage water tank 4 from melting away in a relatively short time.