A content management system formed from a playback apparatus that requests and plays content, and a content management apparatus that manages duplication and deletion of content. The playback apparatus notifies group information of the playback apparatus to the content management apparatus, acquires information from the content management apparatus showing whether requests are permitted, and duplicates/deletes content. By judging whether the playback apparatus belongs to a group, and notifying whether a duplication request is permitted or rejected, based on in-group and out-group remaining numbers that show the remaining number of duplications permitted of apparatuses in-group and out-group, respectively, the content management apparatus relaxes restrictions on in-group content duplication as compared with out-group content duplication, and thus improves convenience for users in a home network, while protecting the rights of copyright holders, with respect to content duplication and usage.