When a general-purpose search service is used, a number of pieces of information searched according to a keyword input by a user is merely displayed. If there are a number of search results, it is difficult to learn the content of the search result. A clustering module acquires a plurality of search results searched by a general-purpose search service, performs a clustering process to the search results, and displays the clustering result. Also arranged is a converter module which converts the search result provided by the search service into a format that is processed by the clustering module.