Abstract: Disclosed is an apparatus for controlling the amount of secondary air fed into an internal combustion engine. The apparatus includes an independent means for rapidly applying an absolute pressure signal to a secondary air flow control means, so that secondary air is rapidly supplied into the engine when the secondary air flow control means is being reset in its initial position, and then, next, a rich signal is applied. Thus, the equivalent air-fuel ratio can be correctly controlled, without delay, in response to changes in the operating condition of the engine.