A digital rights management system (1) includes a content server (30) that stores contents created by content creators, a mobile device (21, 22) that acquires and uses a desired content from the content server, and a data preservation server (40) that preserves the content used by the mobile device so as to enable the content to be uploaded and downloaded. The content server is configured to create rights information for the content, the rights information containing availability of backup saving of the content in the data preservation server, and to deliver the content and the rights information to the mobile device in response to a request from the mobile device. The mobile device is configured to create backup data when using the content based on the availability of backup saving and transmit the backup data to the data preservation server for preservation of the backup data.