An airflow control valve is composed of a housing forming an air passage therein and an electromagnetically driven valve disposed in the air passage. The valve divides the air passage into an upstream passage having an air inlet port and a downstream passage having an outlet port open to an exhaust pipe. A barrier facing an exhaust gas blown back from the exhaust pipe is formed in the downstream passage in order to reduce an amount of deposits accumulating on and around the valve due to foreign particles contained in the exhaust gas. The barrier may be a dead end space in which the exhaust gas stagnates or a wall interfering with a flow of the exhaust gas. A one-way valve may be disposed immediately downstream of the valve to prevent the exhaust gas from flowing toward the valve.