A key-switch device includes a key-top having retainers formed on the back surface of the key-top, first and second levers disposed under the key-top, each lever including a base-end part and a pair of arms opposing each other and extending from both ends of the base-end part, the first and second levers being connected together rotatably about the substantial center of the pair of arms as an intersecting point, a lever-holding plate capable of retaining each lower end of the first and second levers, and an actuator member attached to and spanned between both the base-end parts of the first and second levers. Further, the actuator member has a concave slide-retainer-receiving part with the open top, and the base-end part of the second lever is slidably retained in the slide-retainer-receiving part.