PURPOSE: To improve the traveling performance during high-speed running by shift-controlling the air-fuel ratio to the rich side when the car speed is a fixed value or higher and cutting off exhaust gas circulation in a car performing exhaust gas circulation to the intake system of an engine.

CONSTITUTION: In controlling, first whether the engine temperature is a predetermined value or less or not is judged, if it is the predetermined value or less, a solenoid valve 13 is energized to cut off the communication between EGR passages 8, 9. This is performed by shifting the solenoid valve 13 to the atmosphere side, preventing the negative pressure from being applied to a negative- pressure chamber 10, and closing an EGR valve 11. On the other hand, when the engine temperature is not the predetermined value or less, if the car speed is a predetermined speed or higher, the output of a proportional integrating circuit is shifted to the rich side, then the communication between the EGR passages 8, 9 is cut off. That is, a valve opening signal is fed from a microcomputer 18 to a fuel injection valve 16, thus the fuel injection quantity is controlled and an adequate air-fuel ratio is maintained.