It is also an object of the present invention to provide objective advertisement plan(s). The target specifying information storage part 202 stores information for specifying target attribution including information for specifying information delivery medium of an object to contact with correspondently with searchers' id. The search term storage part 203 correspondently stores a searcher's id, the timing of search, and the term used for the search. The extraction part 204 extracts the timing of search for such search term for each searcher's id, segments the extracted search timing for each searcher's id into a predetermined number in chronological order and then extracts searcher's id belonging to each segment. The advertising medium data determination part 205 extracts information on candidate of information delivery medium for the each segment from the extracted each searcher's id using information for specifying a target and determines candidate(s) of information delivery medium from the extracted candidate of information delivery medium.