An index generation unit (15a) generates an index in which a plurality of combinations of query data that is a collation source and target data that is a collation destination are listed in a predetermined order. A batch generation unit (15b) uses a plurality of combinations of query data and target data in an order according to the index to generate a batch with a predetermined volume. A collation unit (16) calculates a degree of similarity between the query data and the target data for each combination included in the batch, in which processes are parallelized and performed.