1. A push-button switch comprising a substrate having an upper surface, two conductive networks on said surface comprising adjacent but separated conductive paths, a terminal connected to each of said networks, a push-button member operatively connected to said substrate, normally assuming a first position remote from said substrate upper surface and being resiliently movable to a second position closer to said substrate upper surface, and a contact member operatively connected to said push-button member and movable therewith between corresponding first and second positions respectively spaced from and engaging said substrate surface in registration with said networks, said contact member being made of elastic and electrically conductive material and engaging said networks over an appreciable area, thereby to complete an electric circuit between said conductive paths when engaged with said networks, said conductive networks each comprising an outside portion defining said terminal and a helical or arcuate conductive path extending therefrom, the conductive paths of said two networks extending substantially side by side but separated one from the other, the surface of said contact member facing said substrate upper surface being provided with a series of substantially linear downward projections arranged in a pattern of L-shaped lines.