1. An apparatus for setting a user interface according to user preferences, the apparatus comprising: a user-interface-configuration unit which is configured to be notified of a reconfiguration of a user interface element by a user; a user-information-management unit which manages security information of the user that reconfigures the user interface element; and a user-interface-tree-management unit which reconfigures a user-interface tree based on the reconfiguration of the user interface element.