A positioning device that detects a position of a mobile body with a radio navigation positioning unit includes: first and second autonomous sensors obtaining behavioral information on the mobile body; a position detecting unit obtaining an estimated position and an estimated direction by updating a detection result based on the behavioral information from the first autonomous sensor; a map data positioning unit that refers to a map data storage unit based on the estimated position and obtains a map data linked position at a predetermined distance away from a link; a direction detecting unit obtaining a cumulative estimated direction by updating the detection result based on the behavioral information from the second autonomous sensor; and a most probable position estimating unit estimating the position of the mobile body from the estimated positions and directions using the Kalman filter.