A spot welding apparatus includes a stationary frame having a housing formed therein. An upper welding gun is mounted to a length direction of a pressing unit disposed in the housing of the stationary frame. A plurality of lower welding guns are mounted on an outside of the stationary frame and ends of the plurality of lower welding guns selectively face one end of the upper welding gun in a length direction of the lower welding guns by the plurality of lower welding guns. A plurality of actuators are mounted on the outside of the stationary frame. A plurality of link units are disposed between the actuators and the lower welding guns, connect the actuators and the lower welding guns, respectively, and rotate as the actuators are operated.