A related ID information retaining unit relates and stores IDs of game titles related to each other. A game data storage unit stores saved data with a title ID. A title ID acquisition unit acquires a title ID of a game program to be executed, and a related title acquisition unit then acquires another game title ID related to the acquired title ID in a related ID information database. A game data identification unit identifies game data stored in the game data storage unit, based on the title ID acquired by the related title acquisition unit.