At least one of COP and SOP treatments is performed by spraying a predetermined working fluid from spray nozzles (17a, 17b) within an aseptic chamber (9) accommodated with a filler (1) in a predetermined order, when such at least one of the COP and SOP treatments is performed, the predetermined working fluid is blasted toward externally of the filler (1) in the predetermined order while moving a movable spray nozzle (17b) opposing to the filler around the filler (1) from an outer periphery thereof, thus performing the filler cleaning operation. Accordingly, downtime at the drink filling working can be reduced.