1. A data classification device comprising: first designating means for designating a data group to be classified among a plurality of data groups, each of the data groups including one or more data units., each of the data units including a plurality of components; second designating means for designating one or more types of components as classification data; and classifying means for classifying data units within the data group designated by the first designating means into one or more classes based on the classification data designated by the second designating means.