A navigation apparatus and a map matching method are provided. An acceleration sensor detects an acceleration of the vehicle. A gradient determination section determines an angle of inclination of the road link being currently traveled or a value corresponding to the inclination angle. A gradient determination section determines a vertical distance traveled based on the inclination angle and the speed of the vehicle. The accumulated value of the vertical distance is then compared to a set value to determine whether a road link is a downgrade link or an upgrade link. A map matching processor performs map matching processing using a result of the determination and the gradient information.