A data integration processing device configured to integrate a plurality of graphs includes: an integration processing method selecting means 4 for selecting an integration processing method used for integration of inputted graphs; and an integration process executing means 6, having a plurality of integration processing methods, for integrating a plurality of graphs by executing an integration process in accordance with an integration processing method selected by the integration processing method selecting means 4 from among the plurality of integration processing methods. The integration processing method selecting means 4, with respect to each of nodes in inputted graphs, selects an integration processing method used for integrating lower nodes in accordance with frequency that the lower nodes are consistent, when upper nodes are consistent.