A portable terminal device comprising: a first display unit having a first display screen, and an operation unit arranged side by side with the first display screen and having a plurality of area selection keys that are arranged so as to correspond to a plurality of areas in the first display screen, characterized by further comprising: a second display unit having a second display screen that is arranged side by side with the first display screen; and a control means adapted to control the first display unit so that, when any one of the plurality of area selection keys is selected, an enlargement frame is displayed only around an enlargement area corresponding to the selected area selection key, and to control the second display unit so that information on the first display screen that is displayed inside the enlargement frame is enlarged and displayed on the second display screen, wherein: the second display screen has the same shape and size as the first display screen, the first display screen and the second display screen are adapted to be moved between a first form of being arranged side by side in the left and right direction, and a second form of the first display screen and second display screen being folded on top of each other, the plurality of area selection keys include numeric keys, and the locations of the plurality of areas correspond to the locations of the numeric keys, and in the first form, the operation unit is arranged side by side with the first display screen in a direction different from the second display screen with respect to the first display screen. a first display unit having a first display screen, and an operation unit arranged side by side with the first display screen and having a plurality of area selection keys that are arranged so as to correspond to a plurality of areas in the first display screen, characterized by further comprising: a second display unit having a second display screen that is arranged side by side with the first display screen; and a control means adapted to control the first display unit so that, when any one of the plurality of area selection keys is selected, an enlargement frame is displayed only around an enlargement area corresponding to the selected area selection key, and to control the second display unit so that information on the first display screen that is displayed inside the enlargement frame is enlarged and displayed on the second display screen, wherein: the second display screen has the same shape and size as the first display screen, the first display screen and the second display screen are adapted to be moved between a first form of being arranged side by side in the left and right direction, and a second form of the first display screen and second display screen being folded on top of each other, the plurality of area selection keys include numeric keys, and the locations of the plurality of areas correspond to the locations of the numeric keys, and in the first form, the operation unit is arranged side by side with the first display screen in a direction different from the second display screen with respect to the first display screen. a second display unit having a second display screen that is arranged side by side with the first display screen; and a control means adapted to control the first display unit so that, when any one of the plurality of area selection keys is selected, an enlargement frame is displayed only around an enlargement area corresponding to the selected area selection key, and to control the second display unit so that information on the first display screen that is displayed inside the enlargement frame is enlarged and displayed on the second display screen, wherein: the second display screen has the same shape and size as the first display screen, the first display screen and the second display screen are adapted to be moved between a first form of being arranged side by side in the left and right direction, and a second form of the first display screen and second display screen being folded on top of each other, the plurality of area selection keys include numeric keys, and the locations of the plurality of areas correspond to the locations of the numeric keys, and in the first form, the operation unit is arranged side by side with the first display screen in a direction different from the second display screen with respect to the first display screen. the second display screen has the same shape and size as the first display screen, the first display screen and the second display screen are adapted to be moved between a first form of being arranged side by side in the left and right direction, and a second form of the first display screen and second display screen being folded on top of each other, the plurality of area selection keys include numeric keys, and the locations of the plurality of areas correspond to the locations of the numeric keys, and in the first form, the operation unit is arranged side by side with the first display screen in a direction different from the second display screen with respect to the first display screen.