A key switch includes a baseplate, a circuit layer, a keycap and a support rod. The baseplate has a hook and a first through hole neighboring to the hook. The circuit layer includes a first sublayer disposed above the baseplate and having a second through hole, and a second sublayer disposed above the first sublayer and having a third through hole; a portion of the second sublayer extends over the second through hole and forms a first resilient portion; the first resilient portion has four sides, two of which connect to the second sublayer; and the first resilient portion is neighboring to the hook. The keycap is disposed above the baseplate and can move upward and downward in respect to the baseplate. The support rod has a first portion and a second portion; the first portion movably connects to the keycap and the second portion engages the hook.