When torque of a DC motor is dropped down to zero at a stop position, force is generated by deformation of a member for transmitting the torque of the DC motor. The force moves the driven body which is in the stopped state, which results in a shift of the driven body from the stop position. Therefore, a process for stopping the driven body is performed according to the amount of shift by an encoder which periodically outputs a pulse signal according to movement of the driven body, a unit for acquiring velocity information and position information of the driven body based on the pulse signal, a controlling unit for controlling a moving unit based on the velocity information and the position information, and a unit for calculating the amount of shift, which is caused by the force generated by the deformation of the member for transmitting the torque, at the stop position of the driven body.