PURPOSE: To effectively control the speed fluctuation of a rolling roll caused by a twist vibration.

CONSTITUTION: An acceleration current reference is outputted by a speed controller 9 according to the input of a deviation between the speed reference and the detected speed of a motor 1. An ideal speed is calculated from the acceleration current reference by an ideal speed arithmetic unit 11 when supposing that a twist does not occur on a drive shaft 2. The speed of a rolling roll 5 is calculated from the feedback input of a torque standard by a roll speed simulator 101 by using a prescribed operation expression. A deviation between the ideal speed and this calculated value is inputted by a transmission function setting instrument 15, and a value obtained by making a transmission function G (x) work on the deviation is outputted. A value obtained by adding this value and the acceleration current reference is inputted in a current controller 16 as a torque reference. The speed of the motor 1 is controlled with a current standard according to this input.