A vehicle-mounted navigation system initially computes an optimal route from a starting point to a destination. A microcomputer computes the total distance the vehicle has travelled from a signal obtained from an axle sensor and computes the bearing of the vehicle (azimuth) from a signal obtained from a geomagnetic sensor. Then the microcomputer computes the present position of the vehicle from the starting point of the vehicle, its total distance travelled, and its bearing. The system then selects and displays one from among a plurality of arrows stored in a memory, each arrow representing a direction spaced a predetermined angle from an adjacent arrow, to guide the driver from the present position via the next intersection to the destination. This system also detects forked intersections, where two roads are close to the common direction represented by the arrow to be displayed. When a forked intersection is detected, the arrow displayed represents a direction spaced a predetermined angle, either clockwise or counterclockwise, from the common direction.