Internal combustion engine system includes an electric supercharger which supercharges sucked air; a throttle valve which adjusts the flow amount of intake air of supercharged air into a cylinder; an EGR path in which a part of exhaust gas exhausted from the exhaust manifold side is recirculated to the intake manifold side; an EGR valve which adjusts the amount of exhaust gas passing through the EGR path; and an internal combustion engine control unit which controls the throttle valve, the EGR valve, and the electric supercharger. This enables to satisfy both performance of the supercharger and fuel consumption of the internal combustion engine without complicating the structure of EGR.