PURPOSE: To provide the coordinate input device which has high durability and does not require any special parts by providing an operation processing means to calculate a pressed position on a coordinate instructing plate based on pressure detected by a pressure-sensitive means.

CONSTITUTION: When one point on a transparent plate 12 is pressed by a pen, the force is distributed to four fixed points 14a-14d. The peripheries of the fixed points 14a-14d are bent corresponding to the force pressed to the respective points, and the outputs of distortion gauges 16a-16d are changed corresponding to the bending. The outputs of the distortion gauges 16a-16d are amplified by distortion interfaces 18a-18d and A/D converted. The result is dispatched to an operation processor 20 as a distortion output. The operation processor 20 calculates the coordinates instructed on the transparent plate 12. Further, the operation processor 20 drives a display controller 22, and a display position on the screen of a display device 10 corresponding to the coordinate position instructed on the transparent plate 12 is painted in black. Thus, a curve drawn on the transparent plate 12 can be displayed on the screen.