PURPOSE: To compensate the change of an output torque due to the changeover of a valve timing at what controls variably the supercharging volume of a supercharger on the basis of a basic supercharging pressure control quantity in opposition to an engine operation condition, by correcting the basic supercharging pressure control quantity according to a supercharging pressure change rate.

CONSTITUTION: A turbo charger 7 whose compressor portion 8 and turbine portion 12 are respectively provided at an air intake manifold 3 and an exhaust manifold 11, is constituted so that a supercharging volume may be variable by changing an exhaust gas flow passage cross sectional area to the turbine portion 12 by means of an actuator 18 on the basis of a basic supercharging pressure control quantity in opposition to an engine operation condition including an engine rotation speed. Also, a valve mechanism 14 is constituted so that a valve timing may be variable by controlling through a solenoid valve 16 and a changeover control valve 17 oil pressure generated by means of an oil pump 15 driven by an engine. In this instance, the change rate of the supercharging pressure is detected at all times, and an arrangement is so made that the above basic supercharging pressure control quantity is corrected according to the change rate of this supercharging pressure.