PURPOSE: To eliminate the disadvantage that the number of keys per unit area is restricted and to prevent erroneous input operations of simultaneous two or more inputs by making the diameter of guide holes on the front face part of a transparent synthetic resin plate larger and making that on the rear face part smaller to form input pen guiding slope faces.

CONSTITUTION: A keyboard 3 provided with many capacity coupling electrode parts 2 is attached to a fixed plate 1, and a sheet 5 on which key names corresponding to individual electrode parts are displayed is stuck to the front face of this keyboard 3, and a transparent synthetic resin plate 7 on which input guide holes 6 corresponding to key names 4 are provided is stuck to the front face of the sheet 5. The diameter of each guide hole 6 on a front face part 8 of the resin plate 7 is made larger and that on a rear face part 9 is made smaller to form an input pen guiding slope face 10. Thus, the front end part of an input pen is guided along the slope face 10 to perform the input operation smoothly, and restrictions on the number of keys per unit area are relaxed, and erroneous input operations of simultaneous two or more inputs are prevented.