A method and apparatus for searching a rights object and a mapping method and mapping apparatus for the same are provided. The apparatus for searching a rights object includes a transmitting/receiving unit which transmits at least one from a rights object identifier, content identifier list and a rights object to a portable storage device, and a searching unit which searches, from mapping information located in the portable storage device stored with the rights object identifier mapped with the content identifier from the content identifier list, the rights object identifier corresponding to the content identifier by using the content identifier as a search key, and retrieves the rights object stored in a rights slot corresponding to the searched rights object identifier.