A navigation apparatus that detects a position of a movable body includes map data storage means for storing map data; an autonomous sensor that detects information on behavior of the movable body; inertial position determination means for detecting an inertial position-determination position of the movable body, by accumulating the information detected by the autonomous sensor on a result of position determination performed using radio navigation; characteristic position detection means for detecting a characteristic position that is the inertial position-determination position at which the movable body has exhibited a characteristic behavior; correction amount detection means for extracting positional information on a road position corresponding to the characteristic position, by referring to the map data storage means; and position correction means for correcting the characteristic position using a Kalman filter based on a condition that the characteristic position is close to the road position.