To avoid the generation of a pumping loss, a communication passage is formed as a bypass passage between an exhaust port and a combustion chamber in an internal combustion engine. The communication passage is provided with a one-way valve as an exhaust gas return amount adjustment means. The one-way valve includes a spring member having a spring constant set to the value such that a valve body does not displace toward the combustion chamber under the pressure of the exhaust gas in the exhaust port. An opening degree of the one-way valve is autonomously adjusted depending on the amount of air introduced from an intake manifold when the pressure within the combustion chamber becomes negative in the intake stroke. Then inside of the combustion chamber is kept at substantially the atmospheric pressure with the exhaust gas returned to the combustion chamber via the communication passage and the aforementioned air.