Abstract: A key switch includes: an outside frame in the shape of a hollow square, a protruded post at each of two ends of a first side of the outside frame, the protruded post being capable of sliding inside a slide slot on a key top, and a hinge part at each of two ends of a second side of the outside frame, the hinge part being hinged to a fixing slot on a bottom plate; an inside frame is inter-hinged to the outside frame, forming a square shape, having a hinge rod at a middle section of the first side, the hinge rod being capable of sliding inside the slide slot on the bottom plate, and a square-shaped snap part at each of two ends of the second side, the snap part being snapped and fastened in a snap slot on the key top; the key top has at least a slide slot and a snap slot; the bottom plate has at least a fixing slot and a slide slot.