A high efficiency spark plug operative to produce negligible waste materials discharge from the combustion engine with high power output and low fuel consumption. The spark plug has an upper chamber formed by an annular partition ring mounted at an upper position of the cylindrical cavity located in the lower portion of the shell of the spark plug. A cylindrical sleeve mounted in the cavity and located below the annular partition ring. A horizontal annular shoulder in the cylindrical sleeve extending in a horizontal position and separating the interior of the cylindrical sleeve into a middle chamber and a lower chamber. The annular shoulder formed the grounding electrode with an edge of its inner opening located in a spaced manner from the spark tip of the central electrode.