Further, an attention-calling mark for causing the occupant to recognize an obstacle on the scheduled travel course may be added to be displayed at the front windshield 15. In FIG. 16A, an X mark being the attention-calling mark 56 is displayed at a position behind a large-sized vehicle 55 parking/stopping on a road. In consideration of the purpose of the nature thereof, it is preferable that the attention-calling mark 56 is displayed in a striking color such as red and orange, and more preferable that the attention-calling mark 56 is displayed as being blinked.