Provided are an image display device, a key input for controlling the image display device, and a corresponding operating method. The method includes detecting an input of at least one of control keys provided at a predetermined area on the image display device and displaying a control key OSD corresponding to the at least one control key, receiving an input of one of the control keys while the control key OSD is displayed and changing the displayed control key OSD to select key OSDs for selecting menu items corresponding to the inputted control key, and displaying the select key OSDs.