Generally, in a machine provided with a servo motor controller which has a position feedback loop, a speed feedback loop, and a current feedback loop, a current instruction value is preset to the voltage that corresponds to the frictional torque at the time when the motor starts to rotate and/or when the direction of rotation is reversed in order to compensate the delay of response of the motor caused by the frictional torque. According to the invention relating to an improvement in this technology, the value of an integration element constituting the speed control unit is inverted according to a function after the speed instruction of the motor has changed from a positive value to a negative one or vice versa, or after a measured speed of the motor has changed from a positive value to a non-positive one or from a negative value to a non negative one. The output value is then added to the current instruction value or to the integration term thereof, thereby improving the delay in response and decreasing errors in the machine working.