When an elevated road and a usual fly-under road are located in a stacked state, two roads are shown in overlapped lines on a display unit of a car navigation system in a subject vehicle. When the subject vehicle travels the fly-under road, the elevated road is shown in a translucent state. Thus, a user of the subject vehicle can recognize a state of the fly-under road the subject vehicle is traveling. In contrast, when the subject vehicle travels the elevated road, the elevated road is shown in a non-translucent state. The elevated road thereby becomes easy to see, so its advancing direction can be easily seen.