PURPOSE: To correct the erroneous correction of the ignition timing based on the erroneous judgement of the knocking by correcting the ignition timing to the ignition delay side to judge the pseudo knocking according to the vibration level of the vibration condition after correction of the ignition delay side when generation of the knocking is judged by a knocking judging means.

CONSTITUTION: The output signal of a knocking sensor 58 mounted on a cylinder block is received by an ECU 70 to judge whether or not the engine is in the knocking controllable range. If the judgement of YES is made, a judgement whether the engine operating condition is in the range where the vibration attributable to the hammering or collision of the piston is generated as the pseudo knocking is made based on the two-dimensional map of the engine speed and the load. If the judgement of NO is made, the peak value in the frequency range specific to the knocking is compared with the level of judgement to judge the generation of the knocking. On the other hand, when the judgement of YES is made, the corrected amount of ignition delay is read, and is subtracted from the calculated basic ignition timing, and the value is set to the ignition advance.