To provide a mobile communication terminal device where a power consumption for lighting is reduced while the displaying of an LCD screen is confirmed.

With a first invention, based on detection of a prescribed operation at a mobile communication terminal device, a first lighting part is controlled to operate to light a liquid-crystal display while a second lighting part is not operated for a key to be lit. With a second invention, based on detection of a prescribed operation at the mobile communication terminal device, the first lighting part is controlled to operate to light the liquid-crystal display part for a first time period while the second lighting part is operated to light the key for a second time period shorter than the first one.