To protect a plastic intake manifold of an internal combstion engine from heat possessed by exhaust gas recirculation gas, a cooling device is arranged between the plastic intake manifold and an exhaust gas recirculation valve. The cooling device cools the exhaust gas recirculation gas by means of a coolant. A gas discharge part of the cooling device constitutes a pipe portion which penetrates through an exhaust gas inlet hole of the intake manifold keeping a given space between an outer wall of the pipe portion and an inner wall of the exhaust gas inlet hole. The pipe portion may be a leading end portion of an exhaust gas recirculation pipe extending from an exhaust system of the engine.
