To provide a can treatment mechanism simple in structure, capable of treating a can so as to easily remove the drink remaining in the can or the solvent bonded to the can be dry the can and capable of simplifying a recycle process.

A can 2 is supplied to the gap between a pair of collapsing rollers 10, 20 and slits communicating with the outside and inside of the can are formed to the can while the can is collapsed. Blade parts 12 and spacers 13 are alternately provided to one collapsing roller 10 so as to be arranged in an axial direction and blade parts 22 and spacers 23 are alternately provided to the other collapsing roller 20 so as to be arranged in an axial direction. The blade parts 12 of the collapsing roller 10 are opposed to the spacers 23 of the collapsing roller 20 and the blade parts 22 of the collapsing roller 20 are opposed to the spacers 13 of the collapsing roller 10.