A membrane switch device includes first and second membrane layers, a spacing layer between the membrane layers, and a flexible printed circuit board. The first membrane layer includes a first surface and first conductive wires on the first surface and extending to a first wire area to form first contact pads. The second membrane layer includes a second surface and second conductive wires on the second surface and extending to a second wire area to form second contact pads. A wire-connecting end of the flexible printed circuit board is between the first membrane layer and the second membrane layer. A first protection layer of the flexible printed circuit board and the first contact pads are not overlapped with each other, and a second protection layer of the flexible printed circuit board and the second contact pads are not overlapped with each other.