PURPOSE: To precisely finish a mouth of a container by connecting three rolls to a rectilinear block including a bearing box of a rectilinear roll and an arm of an oscillating roll with a link and bringing it close to a shaft center with advance of the rectilinear block so as to clamp the container.

CONSTITUTION: A shaft 8 is a rotation center of an oscillating arm 6 as well as that of an arm 9 of a scrap guide. A link 10 is connected to the arm 9 with a pin 11 at one end. A knife 15 is placed on a tool rest 16, and an angle, height and position in the fore and aft direction of its edge can be adjusted. A cylinder 17, an actuator for moving the tool rest 16, moves forward after a block 2 is moved forward and a container is clamped by a driving roll 18 and two oscillating rolls 19, and the container is fully rotated so as to finish cutting. A scrap is guided by a guide fitting 12 and sent by an air gun and so on to a chute 20.