A knock correction amount computation portion computes, on the basis of intensity of a knock in a case where the presence of an occurrence of the knock is determined, a knock correction amount by which to move a spark timing of the internal combustion engine to be on a retard side and returns the knock correction amount to be back on an advance side in a case where the absence of an occurrence of a knock is determined. In a case where a value of the knock correction amount to be on the retard side becomes equal to or exceeds a predetermined value, the knock correction amount computation portion limits and holds the knock correction amount at the predetermined value and returns the limited knock correction amount to be back on the advance side in a case where the absence of an occurrence of a knock is determined.