A data card 101 with music data accumulated therein is inserted into a portable telephone 110 to fetch the music data into the portable telephone, and application software suitable for a music data format prescribed in association with the music data is selected from among a plurality of pieces of application software (131, 133) stored in a server 130 located remotely, and is downloaded. Through this configuration, the application software associated with the music data can be downloaded from the server to the portable telephone by the user's selection.