An apparatus has a parameter initial value calculator, a force reference impression part, an evaluation data measurement part, an allowable value setting part, a viscosity parameter calculator, an end determining part, and an inertia parameter adjusting part. The force reference impression part intermittently supplies a force reference to an impedance controller. The evaluation data measurement part measures setting time of time response, an overshoot amount, and the number of vibration times. The allowable value setting part sets allowable values of the overshoot amount and the setting time. The viscosity parameter calculator calculates a viscosity parameter with which the setting time becomes shortest. The end determining part determines the end or continuation of the process by comparing the adjustment values with the allowable values. The inertia parameter calculator adjusts the inertia parameter according to the adjustment values of the overshoot amount and the setting time.