To provide a driving device for rolling mills with which torque transmission is released at an arbitary set torque value with respect to overload torque.

The input torque from a motor is transmitted to spindles 20A, 20B after decelerating with output gearshafts 32A, 32B of a driving machine and transmitted to mill rolls 10A, 10B and overload preventing devices 100A, 100B having coupling assemblies for which tightening torque generated by oil pressure is utilized are provided between these output gear shafts 32A, 32B and the spindles 20A, 20B. Oil is supplied from a hydraulic pump 50 to this overload preventing device through rotary joints 60A, 60B. When torques detected with torque detectors 80A, 80B are larger than a preset value, the oil is relieved by switching the flow passages of directional control valves 54A, 54B with a controlling means 200. With this controlling means 200, the set torque value for interrupting torque transmission is selected in accordance with rolling conditions.