1. A phrase pair collecting apparatus for collecting hypotheses of phrase pairs based on one or a plurality of seed pairs each consisting of first and second phrases representing a cause and a result, respectively, said phrase pairs each consisting of two phrases assumed to represent causality, each of said phrases including a combination of a noun and a predicate template; said apparatus comprising: seed pair storage means for storing said seed pair; semantic relation pattern storage means for storing a semantic relation pattern between words; word pair storage means for storing a word pair related to any of the semantic relation patterns stored in said semantic relation pattern storage means; semantic relation pattern matching means for determining which semantic relation pattern a noun pair consisting of the nouns in phrases in each seed pair stored in said seed pair storage means matches; and word pair replacing means for replacing the noun pair of said seed pair with each of the word pairs stored in said word pair storage means and being related to the semantic relation pattern determined to be matching said noun pair by said semantic relation pattern matching means, thereby generating a new hypothesis.