A keyboard includes a circuit board comprising a contact terminal, a key cap, a housing comprising at least one key cap hole configured to penetrate the key cap, an elastic support member configured to support the key cap for moving the key cap and to press the contact terminal while the key cap moves in a downward direction, a link configured to guide an elevation movement of the key cap by connecting a first end of the link to the bottom of the key cap; a rotational support plate configured to be connected to a second end of the link and to rotate on the center of the elastic support member, and a fixing support plate comprising a circular groove configured to internally accommodate the rotational support plate.