In a case where the load is not smaller than the predetermined value, the positioning is not completed even when it is determined that the movable body is moved to the position supposed to be the target position, then the movable body is moved to a retry starting position different from the position supposed to be the target position, subsequently a retry operation is performed for moving the movable body from the retry starting position to the position supposed to be the target position, and consequently the positioning is completed when the load becomes smaller than the predetermined value after the retry operation is performed for a predetermined number of times.