To provide a simulation of a mechanical detent.

A clutch 30 performs the simulation of the mechanical detent via a microprocessor 50 controlled by a servomotor 40 by engaging with a wheel 20 arranged on a rail or a surface. A position and a speed of a shaft are compared with a predesignated position threshold value and a predesignated speed threshold value by using the microprocessor arranged on the shat. When the position and the speed of the shaft exceed the predesignated position and speed threshold values, the servomotor is started, and the shaft is accelerated toward a predesignated position by using the clutch 30 controlled by the servomotor 40. Before engaging the clutch, a speed of the servomotor is adjusted so as to almost coincide with the speed of the shaft.