PURPOSE: To prevent damage to an air tube by forming a recessed part over the full length of the periphery of the outer peripheral surface of a cap body, inserting an air tube therein, and inserting an elastic sealing material between the outer surface side of the air tube and the container so that the sealing material can be enlarged or contracted by expansion or contraction of the air tube.

CONSTITUTION: An elastic seal 29 is set in the sealing position, a capsule C is connected to a cylinder body 1, and a push-tool 3 is advanced to a push- position. Next a pressure plate 16 is withdrawn to fasten a plug 12 to a socket 25 by a sleeve 26, the air in an air tube 28 is purged, and the elastic sealing material 29 is contracted to release a cap body 21 from a capsule body 20 so that the cap body can freely travel. After that, the push-tool 3 is returned to the stand-by position, and refuse is put into a refuse-charge part 2. Next, the push-tool 3 is moved to the push-position to push the cap body 21 into the capsule body 20, and air is supplied to the air tube 28 to the sealing material 29, thus performing sealing. By this constitution, damage to the air tube can be prevented.