A point cloud position data processing device comprising: a data receiving circuit having a structure that receives reference point cloud position data, which is point cloud position data of a measured object, and that receives comparative laser scan data, which is obtained by scanning the measured object with laser light while a vehicle travels, the laser light emitted from a laser scanner that is fixed on the vehicle and that is to be calibrated; a comparative point cloud position data calculating circuit having a structure that calculates comparative point cloud position data in a coordinate system of the reference point cloud position data from the comparative laser scan data based on a trajectory the laser scanner has traveled; and an exterior orientation parameter calculating circuit having a structure that calculates exterior orientation parameters of the laser scanner based on a correspondence relationship between the reference point cloud position data and the comparative point cloud position data, characterized in that the exterior orientation parameters of the laser scanner are temporarily set at values containing a margin of error as unknown parameters, and the exterior orientation parameter calculating circuit has a structure that evaluates a margin of a matching error between the reference point cloud position data and the comparative point cloud position data and that calculates the exterior orientation parameters of the laser scanner by searching for values of the exterior orientation parameters satisfying at least one convergence condition by adjusting the unknown parameters, wherein the convergence criterion is selected from the group consisting of a condition in which the unknown parameters converge, a condition in which the margin of the matching error is minimum, and a condition in which the margin of the matching error is not more than a threshold value. a data receiving circuit having a structure that receives reference point cloud position data, which is point cloud position data of a measured object, and that receives comparative laser scan data, which is obtained by scanning the measured object with laser light while a vehicle travels, the laser light emitted from a laser scanner that is fixed on the vehicle and that is to be calibrated; a comparative point cloud position data calculating circuit having a structure that calculates comparative point cloud position data in a coordinate system of the reference point cloud position data from the comparative laser scan data based on a trajectory the laser scanner has traveled; and an exterior orientation parameter calculating circuit having a structure that calculates exterior orientation parameters of the laser scanner based on a correspondence relationship between the reference point cloud position data and the comparative point cloud position data, characterized in that the exterior orientation parameters of the laser scanner are temporarily set at values containing a margin of error as unknown parameters, and the exterior orientation parameter calculating circuit has a structure that evaluates a margin of a matching error between the reference point cloud position data and the comparative point cloud position data and that calculates the exterior orientation parameters of the laser scanner by searching for values of the exterior orientation parameters satisfying at least one convergence condition by adjusting the unknown parameters, wherein the convergence criterion is selected from the group consisting of a condition in which the unknown parameters converge, a condition in which the margin of the matching error is minimum, and a condition in which the margin of the matching error is not more than a threshold value.