PURPOSE: To prevent an increase of mill hysteresis of rolling mill which thickness is controlled by changing roll gap between work rolls.

CONSTITUTION: Intermediate bearings 24a, 24b which can be movably and selectively fixed in the direction along which roll gap is variable are provided in a bearing box 23 which are provided between work rolls 2, 3 and a driving force generator 27, and movable shafts 25a, 25b which are supported with the intermediate bearings and each of motor shafts 28a, 28b of the driving force generator are mutually connected with connecting shafts 26a, 26b on the motor side through universal joints 22. Each movable shaft is moved by connecting the movable shafts to the work rolls while synchronizing with change of interval between both work rolls. Then, the component of a force in the orthogonal direction to the direction of the axial line that is generated in the case that the connecting shafts on the motor side aren't parallel can be supported with the bearing box through the intermediate bearings and the hysteresis of rolling mill due to friction force that is generated by force that presses the chocks against the housing of rolling mill can be reduced as much as possible.