Abstract: A key switch comprising a bottom shell connected with an upper shell for holding a spring plate, a switching mechanism which is comprised of two conducting plates respectively connected to the two opposite terminals of a circuit, and a spring supported key cap, wherein said upper shell has two retaining grooves separated by a projecting strip for holding said two conducting plates respectively in place. The first conducting plate comprises a trigger frame obliquely disposed toward the spring plate and a contact end extending backward from said trigger frame. Pressing on the key cap causes the spring plate to move the trigger frame to carry its contact end to electrically contact the second conducting plate forming into a closed circuit.