To provide a direct injection Diesel engine for reducing an amount of CO (carbon monoxide) in exhaust gas at a low temperature start time and high idling time and reducing blue white smoke concentration at low-temperature start time and at idling operation time of the engine in a low-temperature condition.

A combustion chamber formed into a hollow shape is provided in a piston top surface, a fuel injection device having both a first mode continuously injecting fuel one time in 1 a single cycle and a second mode injecting fuel a plurality of times during 1 a signal cycle is provided, a switch means switching the first/second mode is provided, by switching the fuel injection device to the second mode by the switch means at high idling operation time with no load applied to an engine further with a high engine speed, at low- temperature start time of the engine, and at idling operation time of the engine and at a low temperature, the fuel subjected compressed self ignition, before the injected fuel leads to a wall surface of the combustion chamber.