User enters information of a melody or other musical material and, when necessary, desired parameters. The input information and parameters are transmitted to a server via a network or other communication media. On the basis of the received musical material and parameters, the server creates content by imparting the musical material with an additional value corresponding to the parameters. For example, in the case where the musical material is a melody of a music piece, the server creates, as the content, harmony information, backing information, accompaniment information, musical score picture information, or the like. There may also be created test-listening or test-viewing sample content corresponding to the regular content. The user receives the sample content from the server, and purchases the regular content when the sample content has been found to be satisfactory as a result of the test listening or test viewing.