This invention relates to a rotational speed control system including a plurality of motor drivers for driving motors, and the object thereof is to drive a plurality of motors at the same rotational speed without depending on the number of motor drivers and without depending on the characteristics of each motor driver. A remote controller 31 and a motor driver 202 are connected to a motor driver 201. The motor drivers 201 and 202 control motors M.sub.11 and M.sub.12 at a prescribed rotational speed, respectively. A rotational speed instructing signal 91 indicative of the rotational speed is supplied from the remote controller 31 to the motor driver 201, and further supplied from the motor driver 201 to the motor driver 202. Because the rotational speed instructing signal 91 indicates a rotational speed which is transmitted in a digital value between the motor drivers 201 and 202, both of the motors M.sub.11 and M.sub.12 are driven at the rotational speed indicated by the rotational speed instructing signal 91.