To flexibly perform import of various kinds of object data using only a single automatic conversion tool.

A multi-link key table MLT defining, in conformation with each field (column) of a database of an import destination, a plurality of field names, showing columns having the same attribute, are formed. The field name of a database of an import source is read as a key, and whether a link key matched to the read key is present in the multi-link key table MLT is confirmed. If the link key matched thereto is present, the column of the database of the import destination corresponding to this matched link key is taken as a corresponding column, and the corresponding column is linked with the column of the database of the import source, to which the reading of key is performed. According to this link, importing of data is performed.