[Problem] To measure coordinates of a moving body with good precision.　[Solution] A positioning system 1000 that performs positioning of coordinates of a moving body 100 includes a coordinates acquiring unit 620 that periodically calculates a first coordinates value and a second coordinates value that indicate a position of the moving body, with at least two reference points that differ from each other as references, a coordinates storing unit 650 that stores a previous history value of at least the first coordinates value calculated by the coordinates acquiring unit a prior time or earlier, a comparing unit 630 that calculates a difference between the first coordinates value and the history value of the first coordinates value, and a coordinates finalizing unit 640 that finalizes the second coordinates value as the positioning coordinates of the mobile body in a case of the difference exceeding a predetermined value.