PURPOSE: To provide a damping method which can damp a servo control system without adding particularly a mechanical detector to a driven part to detect the velocity of this driven part.

CONSTITUTION: In a servo control system 10, the revolving angular velocity θm' of the drive shaft of a motor 3 is detected by a detector 6 that is originally provided. On the other hand, the estimated value θa'Λ of the revolving angular velocity of an arm that is driven by the motor 3 is calculated from the revolving angular velocity θm' and a torque T given from the detector 6 and based on a model expression that is previously set in an arithmetic circuit 7. The estimated value θa'Λ is fed back to the control command value of the motor 3 and the system 10 is damped. Therefore, it is not required to provide any mechanical detector on the arm to detect its revolving angular velocity, etc. As a result, the constitution of the arm can be simplified.