PURPOSE: To control the profiles of upper and lower work rolls over a wide range by arranging upper and lower support rolls which can be freely moved back and forth in the direction of the axial center of the upper and lower work rolls with a moving means.

CONSTITUTION: Rolls are arranged in order of the upper support roll 6, upper work roll 1, lower work roll 2 and lower support roll 18 from the upper part towards the lower part. The diameters of the upper and lower work rolls 1, 2 are made constant in the direction of the axial center of roll, the cross sections on the outer circumferential surfaces of both working rolls 1, 2 are circular and also each pair of the support rolls 6, 18 which are situated on the out sides from the width of metal plate 5 are arranged while abutting on each other. The upper support rolls 6 are provided on the tip of the piston rods 14a of cylinders 14 with bearings 11, also arranged so as to be freely movable back and forth in the direction of the axial center of the upper working roll 1, the lower support rolls 18 are inserted into a back-up shaft 33 which is spanned between the housings 10 and the moving means 21 which can be freely moved back and forth in the direction of the axial center of the lower work roll 2.