In order to mitigate a load in communications among an integrated search server, a plurality of search users and a plurality of search servers in an integrated search system, in the present invention, when an integrated search is executed, first, information for narrowing down the search servers is obtained from each search server, and subsequently, the search servers are narrowed down based on this information, and search results are obtained from only the search servers which have been narrowed down. Thereby, there are advantageous effects of reducing memory usage of the integrated search server, and reducing unnecessary network traffic between the integrated search server and each search server.