Abstract: Improvement of combustion stability in retard ignition at the time of starting in a cold state, high output in a full throttle condition, reduction of smoke, and prevention of wear of the cylinder liner caused by oil dilution, are to be attained. In connection with the flow of fuel into each hole and a fuel inflow angle which is determined by the axis of each hole formed in a plate, the fuel inflow angle of an hole directed to a spark plug is set large to reduce an effective flow path area, thereby making the amount of fuel in the hole smaller than in other holes. A shallow cavity is formed in a piston crown face and a small prominence confronting fuel sprays is formed within the cavity.