Provided are a method and apparatus for generating a rights object (RO) by reauthorization. The method includes a second device mutually authenticating a first device, which received the first authorization information from a right issuer (RI), receiving a first RO from the first device, receiving a second authorization information from the first device, generating a third authorization information based on the second authorization information, changing the first RO to a second RO using the second authorization information, and transmitting the third authorization information and the second RO to an unauthorized device.