The music data (output-prohibited music data) downloaded to the client terminal 2 cannot be output until it is formally purchased. In addition, this music data can be reproduced only while the user of the client terminal 2 is being registered to pay the predetermined fixed charges. Therefore, this prevents from hurting the interests of copyright owners or the like. And the client terminal 2 can acquire music data more efficiently, since it does not have to repeat a process of downloading music data.