A navigation system, comprising: a main unit; a medium insertion port (27, 28) disposed on a front surface of the main unit, through which a portable recording medium is loaded into or unloaded from the main unit; a display unit disposed on the front surface of the main unit, the display unit being movable between a closed position where the medium insertion port (27, 28) is covered and an opened position where the medium insertion port is exposed; a limitation section configured to limit movement of the display unit to the opened position; an operation section including first operation buttons as material objects disposed in the display unit and configured to receive an input operation of a user of the navigation system, wherein the operation section is configured to receive a normal input operation of the user via the first operation buttons of the operation section, to perform a first function, and is configured to receive a special input operation of the user via the first operation buttons of the operation section, different from the normal input operation, to perform a second function, wherein the second function is to remove the limitation by the limitation section; and a removing section configured to remove the limitation by the limitation section when the operation section receives the special input operation of the user; characterized in that the display unit includes a touch panel on which second operation buttons are displayed as immaterial objects, wherein the touch panel is configured to display a move button for causing the display unit to move to the opened position, and wherein the limitation section is configured to limit the movement of the display unit to the opened position by limiting the display of the move button. a main unit; a medium insertion port (27, 28) disposed on a front surface of the main unit, through which a portable recording medium is loaded into or unloaded from the main unit; a display unit disposed on the front surface of the main unit, the display unit being movable between a closed position where the medium insertion port (27, 28) is covered and an opened position where the medium insertion port is exposed; a limitation section configured to limit movement of the display unit to the opened position; an operation section including first operation buttons as material objects disposed in the display unit and configured to receive an input operation of a user of the navigation system, wherein the operation section is configured to receive a normal input operation of the user via the first operation buttons of the operation section, to perform a first function, and is configured to receive a special input operation of the user via the first operation buttons of the operation section, different from the normal input operation, to perform a second function, wherein the second function is to remove the limitation by the limitation section; and a removing section configured to remove the limitation by the limitation section when the operation section receives the special input operation of the user; characterized in that the display unit includes a touch panel on which second operation buttons are displayed as immaterial objects, wherein the touch panel is configured to display a move button for causing the display unit to move to the opened position, and wherein the limitation section is configured to limit the movement of the display unit to the opened position by limiting the display of the move button.