To provide a content management system for unitarily managing content sale and resale/transfer, producing a scarcity value by limiting the number of content to be sold and being controlled so as to enable only a user acquiring a content right to reproduce the content.

When a user of a client 140 makes an instruction to purchase content, a content management server 110 receiving the request establishes the purchase under a fixed condition if within the range of the purchasable number of content, registers the user as the content right owner of the content and transmits reproduction control information to a user management server 120. When the user purchasing the content makes an instruction to reproduce the content, the client 140 acquires the reproduction control information from the user management server 120 and reproduces content data on the basis of the reproduction control information.