PURPOSE: To reuse a filter casing by taking out a charcoal filter, discharging the spent charcoal from the filter casing, and cleaning the filter casing in the exhaust system of ventilating and air-conditioning equipment of atomic power facilities, etc.

CONSTITUTION: The discharging and cleaning device is composed of a rolling- over structure 2 for discharging the spent granular filter medium from the filter casing 10, a dry cleaning device for cleaning a carrier 3 for carrying in and out the casing 10 and the casing 10, a container 5 for recovering the spent granular filter medium, and a dust collector for sucking generated fine powder. Namely, the rolling-over structure 2 is turned to discharge the spent charcoal from the casing 10, the cleaning device is then operated, and the casing 10 can be cleaned. Accordingly, the filter casing can be reused, and the running cost can be reduced.