PURPOSE: To accomplish excellent combustion without ignition delay by providing a main fuel injection means, which injects fuel into an auxiliary chamber during the latter half of a compressing stroke, and an auxiliary fuel injection means, which injects fuel into an auxiliary chamber after bottom dead point of a piston during scavenging.

CONSTITUTION: In a two-cycle diesel engine, a main chamber 4 is formed on the top face of a piston 2, while m auxiliary chamber 9 is formed inside a cylinder head 3, and these are connected with each other by a nozzle hole 10. In the auxiliary chamber 9, a fuel injection nozzle 11 and a glow plug 12 are adjacently arranged. In this case, a plunger 21 of a fuel injection pump is rotated synchronously with a crank shaft, and at the same time, shifted laterally via a cam 24a, a roller 27a, and a compression spring 26. According to the left-hand movement of the plunger 21, a notch 32 and a fuel supply passage 28 are communicated with each other so that fuel is fed to a pressure chamber 23. In addition, according to the right-hand movement of the plunger 21, a port, 31 and a delivery passage 30 are communicated with each other so that the fuel is fed to the fuel injection nozzle 11.