Roller actuating device for flattening machines used for metal products in the shape of sheet metal, strips or the like, also used with similar machines for other applications, comprising a device for transmitting motion to driven rolls (8), extremely functional and capable of transmitting higher torques as well as their independent control. Such device overcomes the frequent problems concerning the space available for installing gimbal adapters. This can be achieved by using adapters (4) provided with teeth which, with the same flange diameter, are able to provide higher torques, and in any case, can be used in any applications in which it is necessary to have reduced operating angles of the adapters.