PURPOSE: To retrieve the information with more approximation in the sense of a user even with a pair of key words having the directional relation by providing an information retrieving means which checks a key word storage means and a relationship storage means after interpretation of the retrieving conditions designated by a retrieving condition input means and then takes out the information having the relationship higher than the threshold value.

CONSTITUTION: A relationship storage means 5 hold two types of relationship between key words. An information retrieving means 6 interprets the retrieving conditions designated by a retrieving condition input means 4 to check a key word storage means 3 and the means 5 and then takes out the information having the relationship higher than the prescribed threshold value. Therefore the relationship between two key words can be dealt in two types, that is, in a case where one of both key words is included in a retrieving request with the other following the information respectively and vice versa. Thus it is possible to retrieve the information with more approximation in the sense of a user even with a pair of key words having the directional relation in terms of the higher-lower rank relation, etc.