A document filtering scheme capable of reducing the number of erroneously selected non-relevant documents without reducing the number of correctly selected relevant documents is disclosed. a non-relevant profile expressing non-relevant documents that are judged as having high similarities with respect to a relevant profile expressing a user's request but not matching with the user's request is utilized in addition to the relevant profile, such that each search target document for which the similarity with respect to the relevant profile is higher than a prescribed threshold for the relevant profile and the similarity with respect to the non-relevant profile is higher than a prescribed threshold for the non-relevant profile is removed as a non-relevant document.