To provide a navigator by which the accuracy of the position of an own vehicle can be enhanced by a method wherein the position of a road as a candidate for a map-matching operation is corrected gradually along the road by using an absolute position which is positioned by a GPS satellite.

A moved distance and a changed direction are detected by a self-contained sensor part 1. The moved distance and the changed direction are added to a previous estimated position by an estimated-position computing part 3 so as to find a recent estimated position. Road data near the estimated position is read out from a map-data storage part 5. A position on a candidate road which is map-matched by a map-matching processing part 6 is found. In addition, a position which is closest to an absolute position positioned by a GPS-data reception part on the candidate road is found. The position of the former is corrected by the position of the latter by a candidate-road position correction part 9 while the reliability degree of the position of a GPS, the reliability degree of the distance of a self-contained sensor and a distance difference are used as parameters. The position is displayed on a display part 7 together with map data.