A content distribution system, a content distribution method and a terminal device are capable of effectively preventing disadvantages of users who formally bought content. In the content system in which a distribution server and a terminal device are connected through a network, even content is taken out from a storage means of the terminal device to the outside later, the content always carries user identification information, so that even the user having the content distributes the content over the network illegally, the distributor of the content can be found with sure.