7. The text mining device of claim 6 , wherein said topic involvement degree calculation unit calculates the topic involvement degree so as to be smaller, as closeness to a transition boundary of a topic of the text element when calculating the topic involvement degree.
6. The text mining device of claim 1 , wherein said topic involvement degree calculation unit calculates the topic involvement degree so as to be smaller as the text element more highly corresponds to a topic other than the analysis target topic when calculating the topic involvement degree.