A device and a method for starting an internal combustion engine, provided with an exhaust turbine turbocharger, an electric motor generator, a power storage unit, an engine rotation starter device, injectors, and a control device that controls the electric motor generator, the engine rotation starter device, and the injectors, wherein when an engine rotation activation start signal is input and the rotational frequency of the exhaust turbine turbocharger reaches an engine rotation-activation-starting rotational frequency, the control device starts driving the engine rotation starter device, and when the engine rotational frequency reaches a fuel-supply-starting rotational frequency, the control device starts driving the injectors, thus improving the starting performance of the internal combustion engine.