1. A data classification supporting method for classifying unknown data on any cell with a classification map comprising a plurality of cells having cell vector data decided on the basis of prescribed learning data, comprising steps of: comparing said cell vector data of each said cell with said unknown data; deciding said cells having said cell vector data firstly to nthly (n: integer of at least 2) close to said unknown data on the basis of results of said comparison between said cell vector data and said unknown data; and displaying a minimum cell mark indicating minimum said cell and a similar cell mark indicating similar said cell on said classification map while deciding said cell having said cell vector data firstly close to said unknown data as said minimum cell and deciding said cell having said cell vector data secondly to nthly close to said unknown data as said similar cell.