A device and method for using a rotating key on a mobile terminal is provided. The mobile terminal includes a plurality of dome switches which can detect a contact signal when pressed and a plurality of contact surfaces which can detect the position of the rotating key in each direction of rotation. The device and method comprises a folder opening/closing sensor for detecting whether a folder of the mobile terminal is opened or closed; first and second display sections for displaying menus or data according to the operation of the rotating key; and a control section for controlling the mobile terminal to display a menu or data selected by the operation of the rotating key on the first display section or the second display section according to an output from the folder opening/closing sensor.