A spatial mapping generation means (81) generates a spatial attribute mapping which maps data for a search object upon a space in which similarity with other data can be determined. A perspective mapping generation means (82) generates a perspective attribute mapping which maps one or more imparted data to members of a totally ordered set. A spatial attribute information generation means (83), by using the spatial attribute mapping to convert the data for the search object, generates spatial attribute information corresponding to the data. A partial set generation means (84) partitions the set of spatial attribute information in accordance with acceptable neighborhood range criteria, and creates sets of search object data corresponding to each of the partitioned spatial attribute information as partial sets of the search object data. A mapping means (85), using the perspective attribute mapping, maps each of the partial sets to a member of the totally ordered set.