1. An information matching apparatus comprising: a processor; and a memory coupled to the processor, wherein the processor executes: calculating matching result values representing identicalness, similarity, and relevance between a plurality of records by matching the plurality of records based on a specified judgment criterion, each of the plurality of records including sets of values corresponding to items; generating frequency distribution information in which the calculated matching result values are used as classes; outputting indices used for evaluating and visualizing a plurality of matching results based on the frequency distribution information generated at the generating, the indices including a histogram of the matching result value; adjusting a threshold corresponding to the specified judgment criterion based on the generated frequency distribution information to generate an adjusted judgment criterion for whether the records match; changing the specified judgment criterion based on an adjusting threshold; outputting the adjusted judgment criterion with the output indices; and re-outputting indices corresponding to the changed judgment criterion.