A map image showing a current position and its surroundings, a route, and an arrow are displayed and superimposed on one another. The arrow has a base indicating the current position and a length indicating a predetermined distance along the route. The arrow has the transparency adjusted to be half transparent to make the map image and route discernible. The arrow moves along with the current position as a vehicle travels on the route. When the route is rectilinear, the shape and length of the arrow do not change. When the route is turned left at an intersection, the arrowhead is turned left after reaching the intersection. Since the arrow is displayed along the route, the arrowhead is disposed on a road to which the vehicle is brought by a left turn made on a road on which the base is disposed.