A time-series signal input section 205 inputs a time-series signal whose on state and off state are repeated alternately. A similar rhythm search section 206 searches a plurality of pieces of rhythm data stored in a data storage section for rhythm data having the same fluctuation pattern as or a similar fluctuation pattern to the time-series signal input to the time-series signal input section 205. A music-associated information storage section 204 stores music-associated information associated with the piece of music corresponding to the rhythm data in association with the rhythm data. A search result generation section 207 generates the search result using the music-associated information (information of title, etc.,) stored in association with the found rhythm data and outputs the search result through a search result output section 208.