PURPOSE: To use a see-through type touch panel as a keyboard and to realize the input processing for a large quantity of information with reduced fatigue by attaching an attachable/detachable structure of the touch panel to a display device and then putting an information display means on the display device after removal of the touch panel.

CONSTITUTION: In a normal state a keyboard stage 3 is stored into a storing space 10 of a case 5 and the display data are selected with push of a prescribed position of a see-through type touch panel 1 set at the front of a CRT 4. When the panel 1 is used as a keyboard type input device, the stage 3 is drawn out toward an arrow AR and a roller 13 is set at the front recess part of the space 10. In this case, the tip boss of an arm 2b moves along a guide groove 11 and a support board 2 attached with the panel 1 is set on the stage 3. Thus the panel 1 can be used as a normal keyboard type input device.