A position information estimating method and apparatus are provided, wherein the position information estimating method includes estimating initial position information of a vehicle based on motion information of the vehicle that is obtained from one or more sensors, calculating search position information of one or more objects included in an image of surroundings of the vehicle based on the initial position information, evaluating a final reliability of each of the one or more objects based on the initial position information and the search position information, obtaining a filter adaptation parameter corresponding to a weight of the search position information based on the final reliability, and estimating final position information of the vehicle based on the initial position information, the search position information, and the filter adaptation parameter.