Correspondence relationships between two laser scanning point clouds are easily determined with high accuracy. A data processor includes a laser scanning point cloud acquiring unit and a laser scanning point cloud correspondence relationship determining unit. The laser scanning point cloud acquiring unit acquires a first laser scanning point cloud that is obtained in a first time period and a second laser scanning point cloud that is obtained in a second time period. The laser scanning point cloud correspondence relationship determining unit determines correspondence relationships between the first laser scanning point cloud and the second laser scanning point cloud on the basis of a laser scanning point cloud relating to a fixed object. The fixed object is contained in both the first laser scanning point cloud and the second laser scanning point cloud and does not change between the first time period and the second time period.