PURPOSE: To improve the acceleration performance from the low speed region by delaying the fuel injection timing of a Diesel engine and increasing the supercharge pressure, when the exhaust temperature is lower than the min. temperature at which a supercharger operates effectively.

CONSTITUTION: A controller 23 calculates the injection timing on the basis of each detection value of an engine revolution speed detector 20 and the load detector 21 such as control rack position detector, etc., and controls a hydraulic timer through a driving circuit 26 and a pressure control valve 16 and controls the fuel injection timing of a Diesel engine. The controller 20 delays the injection timing in proportion to the temperature difference when the shift position by a shift selector 25 is at the advance position and the exhaust temperature detected by an exhaust temperature detector 22 is lower than the min. exhaust temperature at which a supercharger operates effectively.