The present application discloses a key switch and a keyboard provided with the key switch, including base, an upper cover, a button arranged between the base and the upper cover, an elastic member disposed between the lower end of the button and the base and a buffer member disposed on the outer side wall of the button, a limit structure for positioning that buff is arranged on the button, an upper end of that button passe through the upper cover and is expose to the outside of the upper cover, when the button is pushed down, the cushion contacts with the base when the button is moved to thefirst position, after the button is released, the button starts to rebound, when the button is rebounded to the second position, the cushion contacts with the upper cover, and the cushion contacts with the upper cover or the base instead of the upper and lower ends of the button, thereby avoiding collision between the button and the upper cover or the base and reducing key press sound. The limit structure can ensure the stability of the connection between the cushion and the button, prevent the cushion from being dislocated with respect to the button, effectively avoid the problem of the cushion falling off, ensure the mute effect, reduce the maintenance times, and prolong the service life of the key switch.