It is preferable that the prior notice sound is emitted concurrently with prior notice displaying at the first and second display devices 3, 4. The prior notice sound may be emitted using a plurality of speakers 88 arranged to surround a driver's seat in the automobile 14, for example, as illustrated in FIG. 2 and controlled by the automated driving control unit 7 of the automated driving system 2. The speakers 88 may serve as apart of a surround stereo audio system that forms a three-dimensional sound field in the automobile 14.