PURPOSE: To prevent sobbing vibration, by providing a torsional vibration rate computing means for computing the variation rate of torsional vibration amount and a fuel injection amount compensating means for compensating the fuel injection amount of the engine in accordance with the variation rate of the torsional vibration amount.

CONSTITUTION: A torsional vibration amount detecting means detects the torsional vibration amount of drive system of the Diesel-engine, a torsional vibration amount engine comparing means compares the above-mentioned torsional vibration amount with a predetermined value, and a vibration variation rate computing means computes the variation rate of the torsional vibration amount. As a result, when the torsional vibration amount is greater than the predetermined value, a fuel injection amount compensating means compensates the fuel injection amount of the engine in accordance with the variation rate of the torsional vibration amount during a predetermined time period. Thereby, variations in torque due to torsional vibration is cancelled out, thereby sobbing vibration is prevented.