Lane change guidance information is output based on data for the next guide intersection on a route calculated in advance and on detection of the driving lane in which the vehicle is currently driven. The system includes present position detection, direction of advance determination for guide intersections along the preset route, driving lane determination, and guidance information output for instructing the driver when direction to be taken at a guide intersection does not match the current driving lane, whereby adequate guidance information is provided the driver regarding lane changes when the vehicle is driven on a road having two or more lanes.