Abstract: A key assembly, particularly a space bar assembly for a computer keyboard, consists of an elongate cap, an actuating post and two locating posts integrally formed on a bottom of the cap and located respectively at a center and two ends thereof, a key base mounted on an IC board to receive the actuating post, two locating walls mounted on the IC board to receive the locating posts and respectively defining a slot, two mounting seats mounted on the IC board and located respectively near the locating posts and defining respectively a snapping closure, a U-shaped support member having two parallel portions extending through the slots and an intermediate portion snappingly received in the snapping closures.