PURPOSE: To eliminate an error caused by a resistance value in a detecting circuit and a contact resistance of both resistance plates, and to detect with high accuracy a pressure point by applying a voltage between the respective electrodes of the first resistance plate and the second resistance plate, and detecting the voltage between the first and the second resistance plates in a state that the voltage is applied, respectively.

CONSTITUTION: A coordinate input device is constituted by combining the first resistance plate 1 which is transparent and flexible, and provided in parallel with electrodes E1, E2 on both ends, and the second resistance plate 2 having electrodes E3, E4 provided vertically to the electrodes E1, E2 of said resistance plate 1. A DC power source 21 and a voltage detector 22 are connected to the electrodes E1, E2 and E3, E4, respectively, of said first and second resistance plates 1, 2, through switching elements 23W26 of a switching circuit 20. The contacts of the elements 23W26 of this circuit 20 are switched in accordance with the case when the voltage is impressed to the resistance plate 1 or the resistance plate 2, and the case when the voltage between said resistance plates 1, 2 is detected. In this way, in a state that the voltage is impressed between the electrodes E1, E2 and E3, E4 of the resistance plates 1, 2, the voltage between each electrode E1, E2 and E3, E4 is detected, and a pressure point is detected with a high accuracy.