To provide an information retrieval system, a method for information retrieval, a program for executing the information retrieval, and a storage medium comprising the program for executing the information retrieval The information retrieval system according to the present invention comprises: means for generating and storing a predetermined type matrix from said document-attribute matrix, means for generating said document-attribute submatrix from documents being added to said database during a specific time period, means for updating said predetermined type matrix using knowledge with respect to said document-attribute submatrix and for executing the singular value decomposition on updated said predetermined type matrix to execute dimension reduction of all document-attribute matrices stored within said database, and means for retrieving information with respect to a user input query using said dimension reduced document-attribute matrix.