A valid medium issuing system reads a key Ka corresponding to an ID number from a key management book at a request from the script storage system to issue a script medium (MO), decrypts a valid medium certificate in a storage medium delivered from the factory using a key Ka, and generates a script medium (MO). The script medium (MO) is transmitted to the script storage system, and the script storage system records a script document on the script medium (MO). In this process, a decrypting process of a valid medium certificate is performed using the same key Ka, and after confirming the script of the storage medium, the script is recorded. With this configuration, a script document is recorded only for the script.