A file management system comprises an identification device, an administration device, and a supervisory device. A first computing processor of the administration device generates an encrypted file from an original file and encryption information, and stores the encryption information into the identification device. The first computing processor further defines file management information for access control of the encrypted file, and the first computing processor also stores the file management information into the identification device. A second processor of the supervisory device loads the encryption information and the file management information in the identification device to control the usage of the encrypted file. The second computing processor further records the file usage information into the identification device, and transmits to the administration device. The file management system also records the file usage information for clarifying the responsibility of disclosing the content of the encrypted files.