PURPOSE: To hold a rolled stock at rolling center and to prevent the generation of a thickness deviation by arranging a liftable turning roller at the outlet side of a rolling mill and adjusting the center position of the rolled stock.

CONSTITUTION: The rolled stock 2 rolled by a slanted rolling mill 1 is fed out with being rotated at the outlet side of a rolling roll simultaneously with a rolling start. When specified time lapses with the tip of the rolled stock 2 being detected by a 1st tip detector 13a, the lift cylinder 11 which is adjusted at the specified height in advance by a height adjusting device 12 is ascended. And it is supported so as to continue its rotation with the center of the rolled stock 2 coinciding with the rolling center by adjusting the upper face height of a turning roller 10. The deflection while under rolling is thus prevented and the thickness deviation rate can be improved.