To provide a method of downloading a software from a software providing site to a user terminal device and of preparing automatically a medium for an application.
A program 116 for writing-in into a storage medium is downloaded into the user terminal device 102 together with an application data 115, when downloading the application data 115 selected by a user, by accessing the software providing site 111, into the storage medium. The medium for the application is prepared automatically, by starting up the downloaded program 116 for writing-in into the storage medium, using a medium preparation program for the application, and by writing the application data 115 into the storage medium inserted into a storage medium device 103. The application data is prevented from being illegally used by enciphering the application data to be stored in the storage medium, using key information intrinsic to the terminal device 102.