19. An information associating apparatus according to claim 16 wherein: said association degree dictionary composed of an interval association degree dictionary which stores the degree of interval association found by calculating the association degree between said two queries based on the minimum time interval which is the smallest value among time intervals in which each of said extracted queries for each search user from queries used for searching during a past predetermined time interval, and adding said association degrees calculated for a plurality of each of said search users, and a correlation degree dictionary which stores the degree of correlation of key words found by compiling the queries for each search user in a predetermined time interval from queries used for searching during said past predetermined time interval, calculating for each of said users the number of uses of key words among said queries in each predetermined time interval, calculating the number of uses of each key word for all of said search users, and calculating the coefficient of correlation between two key words based on the number of uses of each key word, and further characterized in said initialization unit generating initial groups for grouping key words according to the interval association degree and the correlation degree stored in said interval association degree dictionary, and said grouping unit grouping associated key words by sequentially making the groups which satisfy predetermined conditions into one group using said initial groups and the interval association degree of key words stored in said interval association degree dictionary and the correlation degree of key words stored in said correlation degree dictionary.
19. An information associating apparatus according to claim 16 wherein: said association degree dictionary composed of an interval association degree dictionary which stores the degree of interval association found by calculating the association degree between said two queries based on the minimum time interval which is the smallest value among time intervals in which each of said extracted queries for each search user from queries used for searching during a past predetermined time interval, and adding said association degrees calculated for a plurality of each of said search users, and a correlation degree dictionary which stores the degree of correlation of key words found by compiling the queries for each search user in a predetermined time interval from queries used for searching during said past predetermined time interval, calculating for each of said users the number of uses of key words among said queries in each predetermined time interval, calculating the number of uses of each key word for all of said search users, and calculating the coefficient of correlation between two key words based on the number of uses of each key word, and further characterized in said initialization unit generating initial groups for grouping key words according to the interval association degree and the correlation degree stored in said interval association degree dictionary, and said grouping unit grouping associated key words by sequentially making the groups which satisfy predetermined conditions into one group using said initial groups and the interval association degree of key words stored in said interval association degree dictionary and the correlation degree of key words stored in said correlation degree dictionary. 20. An information associating apparatus according to claim 19 wherein: an initialization unit generates groups including one different key word stored in said association degree dictionary, as said initial groups.