PURPOSE: To discriminate figures, symbols, and characters of a written image by movement of the pen point of a pen to store and display them.

CONSTITUTION: A torque in the direction opposite to the torque applied to a pen point 4 is generated on a root side 5 with one point on a penholder 3 as a fulcrum 6. A certain current is allowed to flow to a resistor 8 coming into contact with the root side 5 to generate a voltage corresponding to the resistance value in the contact position of the root side 5, and thereby, the torque is converted to an electric signal to store figures, symbols, and characters by a microcomputer 11, and a numerical formula is calculated to display the result on a display part 12. Thus, functions of storage and calculation are fulfilled with one pen, and it is unnecessary to carry a word processor or a desk calculator.