At least one musical instrument, a server computer, a mobile telephone and a communication network form a music performance system; the owner has registered the musical instrument with a client database in the server computer, and a user transmits a request for music data distribution service to the server computer through the mobile telephone; upon reception of the request, the server computer searches the client database to see whether or not the owner has contracted the provider for the music data distribution service; when the server computer finds the owner in the client database, the server computer transmits a set of music data codes directly to the musical instrument so that the mobile telephone is shareable between the musical instrument and another musical instrument.