PURPOSE: To make the thickness shape controlling in the width direction easy by disposing sleeves in contact with rolls, to a pair of upper, lower work rolls provided with roll bending devices and fitting the reinforcing shafts of a specific shape to the inside wall surfaces of the sleeves axially movably.

CONSTITUTION: A pair of upper, lower work rolls 3, 3 provided with roll bending cylinder devices 2 are supported between housings 4, 4, and the reinforcing shafts 5, 5 which are disposed with sleeves 9 in contact with the upper, lower work rolls 3, 3 to the respective upper and lower parts of the rolls 3, 3 in the same direction as that of the rolls 3 and are so constituted as to form large-diameter parts and small- diameter parts provided with suitable parts of differences of level in the shaft barrel parts are axially movably fitted in the sleeves 9, whereby the rolling mill is constituted. With the above-mentioned constitution, the parts of difference of level provided to the reinforcing shafts 5 as means of minimizing the bending of the rolls owing to rolling load are moved, whereby the bending of the work rolls 3, 3 is decreased and the plate shape of the rolled material 12 is improved.