This paper presents a method for automatically generating an association thesaurus from a text corpus, and demonstrates its application to information retrieval. The thesaurus generation method .consists of extracting tenns and co-occurrence data from a corpus and analyzing the correlation between terms statistically. A new method for disambiguating the structure of compound nouns, which is a key component for term extraction, is also proposed. The automatically generated thesaurus is effectively used as a tool for exploring infonnation. A thesaurus navigator having novel functions such as term clustering, thesaurus overview, and zooming-in is proposed.