A control apparatus for an internal combustion engine that can prevent, for instance, an exhaust purification catalyst from being damaged when the employed fuel is changed to a fuel having different properties during an operation. If fuel learning is incomplete while a refueling record exists, the throttle opening of an internal combustion engine operable on a fuel that is obtained by mixing alcohol and gasoline at an arbitrary ratio is limited. Limiting the throttle opening makes it possible to avoid an entry into an operation region where fuel increase is performed. This prevents air-fuel ratio feedback control from being stopped when a fuel change occurs. Consequently, the use of an improper air-fuel ratio that may damage the catalyst can be definitely avoided.