For information about point cloud data, a point cloud data sameness estimation apparatus and a point cloud data sameness estimation system in which accuracy of evaluating sameness is improved are provided. In the present disclosure, a point cloud data sameness estimation apparatus for estimating sameness of objects that are sources of two 3-dimensional point cloud datasets includes a point cloud data acquisition unit configured to acquire first point cloud data and second point cloud data including 3-dimensional point cloud data; a first neural network configured to output a first point cloud data feature, with information about the first point cloud data as an input into the first neural network; a second neural network configured to output a second point cloud data feature, with information about the second point cloud data as an input into the second neural network; and a sameness evaluation unit configured to output an evaluation about sameness of the first point cloud data and the second point cloud data, based on the first point cloud data feature and the second point cloud data feature, wherein a weight is mutually shared by the first neural network and the second neural network.