1. An information classification device for analyzing a configuration of data containing character information, comprising: character information extracting means for extracting predetermined character strings from the character information of the data; labeling means for converting the extracted character strings into a series of label strings by replacing each of the extracted character strings with a label indicating a class of the character string; and label appearance pattern estimating means for estimating an appearance pattern that is defined as a set of different labels repeatedly appearing in the label strings obtained by the labeling means, wherein the labeling means converts the extracted character strings into the series of label strings by converting the extracted character strings into initial label strings, identifying, in the initial label strings, any series of the same label appearing at least twice in a row, and replacing any of the series of the same label with a single label, such that in resultant series of label strings, two or more of the same labels do not appear adjacently; and further comprising: correspondence information storing means for storing correspondence information defining correspondence between classes of the extracted character strings and the labels to replace the character strings, wherein the labeling means replaces, based on the correspondence information, the extracted character string with the label for each class, and wherein: the correspondence information defines, for each of the extracted character strings, correspondence regarding a broader class or a narrower class relative to the class of classified character string; and the information classification device further comprises character information classifying means, the character information classifying means correlating, based on the correspondence information, each label represented by the estimated appearance pattern with an optional class of each of the character strings before the replacement, a broader class relative to the optional class, or a narrower class relative to the optional class, and selecting suitable character information suited to a predetermined combination to classify the character strings extracted from the data.