When it is determined that the shells are set in the second state in an automatic activation mode, a TV receiver and TV display application program are activated, and a TV video signal is displayed on the main display. A full-screen display mode of displaying the TV video signal by using the full-screen display area of the main display, and a partial-screen display mode of displaying the display area of the main display by dividing the display area into a TV video display area and additional information display area are prepared. When the TV video signal is to be displayed on the main display, the TV video signal is displayed by using each of the display modes in accordance with the state of the shells.