5. An information classification device according to claim 4 , further comprising division criteria storing means for storing a predetermined division criterion, wherein: the character information extracting means divides a set of the character strings extracted based on the extraction information into a plurality of partial character string sets based on the predetermined division criterion; the labeling means replaces the character strings included in the partial character string sets with the label for each class; and the label appearance pattern estimating means receives, as an input, a label string obtained by the replacement of the partial character string set by the labeling means to estimate a label appearance pattern.
5. An information classification device according to claim 4 , further comprising division criteria storing means for storing a predetermined division criterion, wherein: the character information extracting means divides a set of the character strings extracted based on the extraction information into a plurality of partial character string sets based on the predetermined division criterion; the labeling means replaces the character strings included in the partial character string sets with the label for each class; and the label appearance pattern estimating means receives, as an input, a label string obtained by the replacement of the partial character string set by the labeling means to estimate a label appearance pattern. 6. An information classification device according to claim 5 , wherein: the predetermined division criterion is set as whether a distance between adjacent character strings in the data is a prescribed value or more; and based on whether the division criterion is satisfied, the character strings are included in different partial character string sets or the character strings are included in the same partial character string set.