PURPOSE: To obtain a PET bottle shredder small in size and simple in structure by discharging air in a PET bottle from which a stopper is removed, collapsing it into a platelike shape and shredding the collapsed PET bottle.

CONSTITUTION: The PET bottle 3 from which the stopper is removed is charged into a shredder 1. A packing 7 of a collapsing part 4 is closely fitted to an opening 10 of the charged PET bottle. When a vacuum pump 9 is driven, the air in the PET bottle 3 is sucked via a sucking pipe 8 communicated to the inside of the PET bottle through the packing 7 to collapse the PET bottle into a platelike shape. The collapsed PET bottle 3 is dropped downward when driving of the vacuum pump 9 is stopped, and is transferred to a shredding part 5. At this time, since a gear motor 12 is rotated, when the collapsed PET bottle 3 drops between rotary tooth groups 11, 12, the rotary tooth groups 11, 12 bite the PET bottle 3, the and PET bottle is shredded by each rotary tooth 23 and is stored in a container 6.