According to one embodiment, a key switch includes a base member, a keycap, a supporting member, and a membrane switch. At least one of the keycap and the supporting member includes a projection portion pressing the membrane switch when the keycap descends. The membrane switch includes a flexible portion bending as being pressed by the projection portion. The base member includes an opening portion which the flexible portion pressed and bent by the projection portion enters.

A keyswitch includes a board, a cap located above the board, a membrane circuit board disposed on the board to make first and second engaging structures of the board protrude from first and second holes of the membrane circuit board respectively, and a lifting device. The lifting device is connected to the cap and the board and includes first and second support members. The first support member is movably connected to the cap and has a pivot end portion. The pivot end portion is movably connected to the first and second engaging structures and has a first abutting portion extending toward edges of the first and second holes along a pivot axis of the first engaging structure. The first abutting portion abuts on the membrane circuit board. The second support member rotatably intersects with the first support member and is movably connected to the cap and the board.

A keyboard may include a top case and a bottom case coupled with each other to define an internal compartment. Multiple internal layers are contained within the internal compartment. The multiple internal layers may include a plurality of keys mounted on a switch plate, wherein a portion of each of the plurality of keys protrudes over the top case; a printed circuit board (PCB) layer disposed under the switch plate; a gasket layer disposed under the PCB layer. The gasket layer comprises a peripheral wall and a bottom floor integrally formed with the peripheral wall. The switch plate is coupled with the peripheral wall of the gasket layer.