1. An information associating apparatus comprising: a query extraction unit which compiles for at least each search user queries that were used in a past predetermined time interval taken from data comprising queries used in order to search for information, a preprocessing unit which calculates the parameters necessary for calculating the association degree between key words included in queries extracted for each search user by said query extraction unit, and an association degree calculation unit which calculates the association degree between key words using the parameters calculated by said preprocessing unit.