ends of the brush roll are smaller in outer diameter than axially intermediate portion in conformity with the chilled roll 1 the pushing cylinders 10 horizontally and diametrically push the necks of the brush rolls 9 somewhere around their primal ends respectively and the bending cylinders 11 horizontally push the necks of the brush rolls 9 somewhere around their distal ends respectively the auxiliary brush rolls 12 are in parallel with the chilled rolls 1 and arranged to abut against the outer peripheries of the chilled rolls 1 from below the brush rolls 9 respectively the auxiliary brush rolls 12 also have wires made of stainless steel like the above mentioned brush rolls 9 the pushing cylinders 13 push necks of the auxiliary brush rolls 12 toward the axes of the chilled rolls 1 respectively the brush rolls 9 and the auxiliary brush rolls 12 are rotatively driven by motors not shown respectively specifically during production of a strip the respective brush rolls 9 are urged to the chilled rolls 1 by the pushing cylinders 10 while being rotated and at the same time the brush rolls 9 are deformed by the bending cylinders 11 in conformity to the crowns of the chilled rolls 1 respectively which causes the wires of the brush rolls evenly contact the outer peripheries of the chilled rolls 1 over the axial lengths thereof to wipe off the oxides adhering to the chilled rolls 1 respectively the effect of cooling the solidified shells at the regions becomes not impaired the oxides are efficiently wiped off when distance between the axis of the chilled roll 1.