PURPOSE: To improve mixing of fuel and air and to improve combustion performance by juxtaposing two swirl chambers in a cylinder head, and providing a means to specify the direction of each injection nozzle for intercommunicating each vortex chamber to a cylinder.

CONSTITUTION: Two swirl chambers 2 and 3 are juxtaposed to each other in a cylinder head 1 in a state that outer parts thereof are overlapped with each other, and a communicating part 4 is formed by the overlapped part. Injection nozzles 5 and 8 to respectively intercommunicate the swirl chambers 2, 3 with a cylinder 6 are formed in the rear surface of a cylinder head 7 by which the swirl chambers 2 and 3 are partitioned away from the cylinder 6. The direction of each of the injection nozzles 5 and 8 is set to a direction in which eddy currents opposite to each other are generated by means of the swirl chambers 2 and 3. A fuel injection nozzle 9 through which fuel is injected to the swirl chambers 2 and 3 along the direction of the flow of swirl is disposed to the cylinder head 1. This constitution improves mixing of fuel and air and improves combustion performance.