An input apparatus of a mobile terminal and its display method are disclosed. The input apparatus of the mobile terminal according to an embodiment includes a keypad having a plurality of keys and generating key signals corresponding to a selection of the keys; a plurality of light emitting elements positioned at the plurality of keys, respectively, for illuminating the keys; a key sensor for sensing the key signals from the keypad; a storage unit for storing the key signals; and a controller for displaying, on the keypad, information corresponding to the key signals by selectively controlling the plurality of light emitting elements based on the key signals.