Control data is generated in response to generation, from a position detector, of position data in accordance with a predetermined scale characteristic. Change scale characteristic is applied in manual operation performed immediately after an operation member has been automatically positioned to a target position. In the change scale characteristic, a start point is established such that control data, corresponding to the target position, of the predetermined scale characteristic is outputted in correspondence with the position data outputted at the time of completion of the positioning, but also a first change portion, including a portion extending from a position of the start point at least up to the target position, is established, so that the control data outputted in correspondence with the position data output gradually varies from data corresponding to the start point to data of the predetermined scale characteristic corresponding to an end point of the first change portion.