A contents management system that centrally manages a disclosure period of contents stored on recording media and distributed to users, while at the same time securing the safety of the contents. A contents management server in the system controls the disclosure period of contents by managing information relating to contents and users, with respect to encrypted contents stored on recording media and distributed to users. Moreover, the contents management server is able to make changes to the various items included in the information relating to contents and users, and is able to control the disclosure of contents using this information immediately after a change.