1. An information processing device for handling data in which a topology has been formed of a plurality of nodes each having attribute values, said information processing device comprising: a topology evaluation unit for obtaining weighting factors of edges connecting nodes, based on attribute values which neighboring nodes on the topology each have, and sorting edges based on the weighting factors; and a node merging processing unit for extracting pairs of nodes connected by edges following the sorted order, evaluating whether or not to merge the nodes based on a predetermined statistical processing algorithm, and performing merging processing of node regions.