A torque base control unit calculates target torque based on an accelerator position and engine speed. The control unit further executes calculation of target airflow rate, calculation of target intake pressure, and calculation of target boost pressure based on the target torque. Target throttle position is calculated based on the target airflow rate, target intake pressure, target boost pressure, actual boost pressure, and throttle passed intake temperature. An assist control unit calculates target turbine power based on the target airflow rate and the target boost pressure calculated by the torque base control unit and calculates actual turbine power based on exhaust information. Assist power of a motor attached to a turbocharger is calculated based on the power difference between the target turbine power and the actual turbine power.