With a new function introduced neither to a file server nor to a client terminal, control of displaying only a file or a folder whose access right is held by a user is enabled by using existing file server and client terminal. A gateway server connected to a file server and a client terminal through a network, which has the function of filtering structure information of a folder and a file that the file server has based on access authorization of a user of the client terminal on the user basis and presenting the filtered structure information of the folder and the file to the client terminal of a user who has access authorization for the folder and the file.