The invention provides a program-downloading system comprising a USIM (1) from and in which data can be read and written via a cellular phone terminal (2) and which holds a given program specification and encryption communication means, and a program server for communicating with the USIM via the cellular phone terminal and providing a program to the universal subscriber identify module according to the given program specification. The program server prepares a program list that can be provided according to a program specification sent out of the USIM via the cellular phone terminal and transmits the program list to the cellular phone terminal, so that when program information selected by the USIM from the program list is received via the cellular phone terminal, a given encryption communication means is selected out of an encryption communication means list transmitted out of the USIM to encrypt a program, which is then downloaded to the USIM.