To provide both a device for washing an automatically opened cover of a vessel having a compact structure and containing content, in which in order to reuse the vessel such as a bottle, a can, a paper pack and a PET bottle containing content and having an opening closed by a cap, opening of the same, discharge of content and washing of the body of the bottle are performed automatically and efficiently, and a method therefor.

Bottles 10 introduced into both a charging conveyor 2 and a vessel-feeding unit 3 are successively sent one by one by a separator 4 and gripped by manipulators 11 of a manipulator part 5 and sent to the position of a cover opening unit 6. Herein, caps are opened and discharged. The bottles 10 are inverted so that the opening parts are made under and content drops by dead-weight and is discharged. The bottles 10 successively subjected to pitch feeding and being in a state gripped by the manipulators 11 are washed and converted to a normal state after washing and moved to the position of a loadfree discharge means 9 and therein the bottles 10 are made loadfree and discharged.