To provide a suction device for a direct injection diesel engine capable of supplying suction air to all area in an engine in an operated condition at a proper swirl ratio, showing high volume efficiency and a proper compression ratio and reducing hydrocarbon, nitrogen oxide, smoke and particulate organic substances in exhaust gas.

A first suction valve 1a provided in a first helical suction port 1 and a second suction valve 2a provided in a second tangential suction port 2 are open at the almost same time near the suction top dead points of pistons. The first suction valve 1a is closed near the suction bottom dead point and the second suction valve 2a is closed a certain time after the first suction valve is closed. A suction control valve 3 provided on the upstream side of the second suction valve 2a in the second suction port 2 is closed when an engine is in low-speed operation and open when in high-speed operation.