A route guidance section compares the current position provided by a current position determination section and the route provided by a route calculation section for detecting an off-route condition. When the off-route condition is detected, a re-searching key as well as the route and current place is displayed on a display section. When the re-searching key is touched, a search is again made for a new route from the current position to the destination. Then, route guidance is again started in response to the re-searching result. When the re-searching key is not touched, the route and current place continue to be displayed while the vehicle carrying the apparatus travles off route, thereby efficiently preventing the apparatus from executing unnecessary re-searching when the driver drives the vehicle off route on purpose.