A slidable input device and a portable apparatus including the same, in which objects arranged in three-dimension or the size of a specific object can be easily manipulated and controlled. The portable apparatus includes an input unit for generating a key-selection signal corresponding to up, down, right or left directions selected by a user and a movement signal corresponding to a direction to which the input unit is moved by the user through an external force; a signal input unit for receiving the key selection signal and the movement signal generated by the input unit; a control unit for carrying out a predetermined operation indicated by the key selection signal and the movement signal inputted by the signal input unit; and a display unit for displaying the object according to the predetermined operation on a screen.