An integrated retrieval scheme retrieves data involved in a plurality of semi-structured documents scattering over open networks and collects the required information item by item from the semi-structured documents through a unified interface without regard to differences in the document structures, presentation styles, and elements of the semi-structured documents.The search scheme receives a query consisting of search items and search conditions from a user. The search scheme finds, according to location data that specifies the location of each of the semi-structured documents, the location of each semi-structured document that contains all search items and converts, if necessary, item presentation styles of the entered query into that of the location found semi-structured documents according to style conversion data, and forms queries for the location found semi-structured documents, and transmits the queries to the found locations and obtains the location found semi-structured documents, and extracts item data from the obtained semi-structured documents according to structure data being used to delimit document into items and attribute data being used for conditional retrieval, and prepares a search result, and converts, if necessary, item presentation styles of the search result into the item presentation styles of each user according to the style conversion data.