FIGS. 12A to 12D illustrate, in the order of time passage, a transition of that the virtual image 46 of the own vehicle displayed at the front windshield 15 performs lane change. First, the virtual image 46 starts as a virtual image 461 in FIG. 12A illustrating a virtual vehicle having appearance and size as if the virtual vehicle is travelling just in front of the front windshield 15. The virtual vehicle moves from a position just in front of the front windshield 15 to the cruising lane 45 to be apart therefrom while changing orientation of the vehicle body as being similar to the actual vehicle along the travel course of the symbol image 44 as illustrated by the virtual images 462, 463 in FIGS. 12B and 12C. Then, the virtual vehicle completes movement to be the virtual image 464 that is oriented to straightly travel on the cruising lane 45.