PURPOSE: To realize a compact size of the device and to improve the operational property by making either one electrode sheet of the X-direct electrode sheet or the Y-direction electrode sheet composing a matrix composition, in a turnup structure.

CONSTITUTION: In a membrane switch, a Y-direction electrode sheet 2 and an X-direction electrode sheet 3 are arranged under a letter sheet 1, and under them, a base plate 4 is placed. Since the Y-direction electrode sheet 2 has an electrode width regulating area x, it is bent and a contact member 5 is exposed through the lower side of the Y-direction electrode sheet 3. The electrode wire of the X-direction electrode sheet 3 is extended to a contact member 6 of the X-direction electrode passing through the area other than the letter sheet 1. As a result, there is the electrode width regulating area x no more, and the length of the electrode sheet extending out of the membrane switch main body can be set freely. Consequently, a compact size of the device can be realized, and a membrane switch system of tablet which can operate at a constant operation force even when the size of the letter sheet is changed can be obtained.