PURPOSE: To prevent an increase in a gap caused by the deformation and the shifting of a disk roll during rolling.

CONSTITUTION: Disk rolls 2U and 2D are arranged opposite to each other in the vertical direction on both sides of a pass center in a position where they are matched with inclined rolls 1R and 1L. And, roller devices 3, 3 which are two shift blocking members, are arranged on the side surfaces on the outlet sides of the rotation of a material H to be rolled of the disk roll 2U (2D), and the rotary shaft of the roller, is set in the radial direction on the side surface of the disk roll 2U (2D). The roller devices 3, 3... are made to come into contact with the side surfaces of the disk rolls 2U and 2D, and rotate following in the rotations of the disk rolls 2U and 2D, thereby blocking the shifting of the disk rolls 2U and 2D.