A turbocharger system for ensuring a sufficient exhaust gas recirculation (“EGR”) amount in all operating conditions, and reducing NOx emission from an engine. The system includes an EGR controller that re-circulates a part of exhaust gas discharged from the engine to an intake side. The turbocharger is a power-assisted turbocharger including an electric motor that assists a drive force of a compressor. The EGR controller controls an amount of exhaust gas recirculated to the intake side so as to inhibit the generation of NOx regardless of an amount of oxygen necessary for combustion of the engine. An electric motor control unit drives the electric motor, by the control of the EGR controller, when the amount of oxygen necessary for the combustion of the engine is deficient.