A content management system including a content management server and a client terminal connected to the content management server via a communication network, wherein the content management server transmits, to the client terminal, a management server ID identifying the content management server and a content deletion request, the client terminal receives the management server ID and the content deletion request from the content management server, determines whether or not the received management server ID matches a management server ID saved on the client terminal side, and if they match, deletes the content saved on the client terminal side, in a removable media, the content corresponding to the deletion request. A content, that is saved in various forms on the client terminal side is disabled for playback at an appropriate timing; accordingly, it is possible to reduce risks such as information leakage to ensure security, and also ensure content integrity.