To enable a volume-reduced waste plastic container to be packaged without producing any troublesome subsequent handling in the case that the volume of the waste plastic container is reduced after it is used as a container of which contents may easily be left and further to cause a manual operation performed at the time of packaging operation producing bad odor or easily stained to be reduced as much as possible.

There are provided a volume reducing means 1 for compressing, deforming a waste plastic container A and reducing its volume; a bag filling means 3 for filling a volume reduced waste plastic container B into a packaging bag 2; a seal closing means 5 for sealingly closing an opening 4 of the packaging bag having the volume reduced plastic container; a transporting means 6 for transporting the volume reduced waste plastic container to the bag filling position applied by the bag filling means; and a control means 7 for controlling operations of the volume reducing means, the bag filling means and the closing means.