Abstract: A pair of rolling machines are arranged in series in alignment with a pass line along which a workpiece to be rolled is passed. The center distance between the first rolls of the first rolling machine and second rolls of the second rolling machine is designed to be not more than 1.5 times the roll diameter. The rotational axes of the first rolls are displaced by an angle of 90° from those of the second rolls and are inclined at an angle of 45° respectively with respect to the horizontal plane. A plurality of dual-purpose calibers are defined between the rolls of the rolling machines to be arranged in the axial direction, respectively. The rolls are shifted in crossing directions to the pass line respectively so as to bring desired dual-purpose calibers in alignment with the pass line.