1. An incorrect hyperlink detecting apparatus for detecting a logical inconsistency of a hyperlink, comprising: a first extracting means for extracting a text out of an HTML file of a hyperlink source; a second extracting means for extracting a text out of an HTML file of a hyperlink destination; morpheme analysis means for dissolving the texts extracted by the first and second extracting means into one or more words, respectively; consistency rate calculating means for calculating a rate that the words of the hyperlink source are included in the words of the hyperlink destination as a first consistency rate, and a rate that the words of the hyperlink destination are included in the words of the hyperlink source as a second consistency rate, with reference to the words obtained by the morpheme analysis means; degree of association calculating means for calculating a degree of association indicating a probability of a correct hyperlink based on the first and second consistency rates calculated by the consistency rate calculating means; and weighting factor setting means for setting a desired weighting factor for a part of speech; wherein the consistency rate calculating means includes: means for calculating assignment points of the words of the hyperlink source by multiplying predetermined basic points by the weighting factor set by the weighting factor setting means; means for calculating assignment points of the words of the hyperlink destination by multiplying predetermined basic points by the weighting factor set by the weighting factor setting means; means for setting a link destination presence flag to 1 if the words of the hyperlink source is present in the hyperlink destination, and setting the link destination presence flag to 0 if the words of the hyperlink source is not present in the hyperlink destination; means for setting the link source presence flag to 1, if the words of the hyperlink destination is present in the hyperlink source, and setting the link source presence flag to 0 if the words of the hyperlink destination is not present in the hyperlink source; means for calculating acquisition points of the words of the hyperlink source by multiplying the calculated assignment points of the words of the hyperlink source by the set link destination presence flag; means for calculating acquisition points of the words of the hyperlink destination by multiplying the calculated assignment points of the words of the hyperlink destination by the set link source presence flag; means for calculating the first consistency rate by dividing a total of the calculated acquisition points of the words of the hyperlink source by a total of the calculated assignment points of the words of the hyperlink source; and means for calculating the second consistency rate by dividing a total of the calculated acquisition points of the words of the hyperlink destination by a total of the calculated assignment points of the words of the hyperlink destination.