A push button of rubber or other resilient material for use with a push-button switch and comprising a hollow tilting wall of a mesa shape. The tilting wall of the resilient push button serving as an operating portion is constructed such that its thickness gradually decreases in going from an upper portion toward an intermediate portion and gradually increases in going from the intermediate portion to a lower portion. A curved surface curving inwardly toward the interior of the switch is formed to extend from the intermediate portion to the upper portion. When pressure is first applied to a key top, the curved surface is bent inwardly toward the lower portion of the switch; and when further pressure is applied to the key top, the surface area of the intermediate portion, which is bent inwardly, is increased until the pressure affects the upper portion of the tilting wall. Then, the direction of curving of the curved surface portion is suddenly reversed and the curved surface curves outwardly, whereby the operator can learn by tactile sensation that a switching operation has occurred.