PURPOSE: To always rotate a work roll or a backup roll by providing a groove on the surface of the backup roll in the circumferential direction and fitting an elastic ring having an outer diameter slightly larger than the outer diameter of the roll into the groove.

CONSTITUTION: The groove 6 is provided on the surface of the roll 3 of the backup roll 2 of a leveler. The elastic ring 4 having an outer diameter slightly larger than the outer diameter of the roll 3 is fitted into the groove 6. While the workroll is rotated, the backup roll 2, too, is rotated. Consequently, the backup roll can be manufactured inexpensively and compactly.