To provide a knocking suppressing device sufficiently suppressing knocking while ensuring responsiveness to knocking, and besides preventing deterioration of fuel consumption.

Knocking is suppressed by performing an ignition retard (S20) when detecting knocking. After suppressing knocking, retarded ignition timing is advanced to be returned to an original ignition timing, and also ignition timing converting processing (R1) is performed which increases based on a map an EGR gas introducing amount according to an advanced quantity.