To provide a supercharging pressure control device capable of quickly increasing supercharging pressure, while preventing an excessive increase in exhaust pressure (back pressure) particularly in acceleration, by properly controlling driving of a turbocharger.

Target upstream side exhaust pressure P3CMD is calculated in response to a deviation ΔP2 between target supercharging pressure P2CMD and detected supercharging pressure P2 (S11, and S12). Limit processing of the target upstream side exhaust pressure P3CMD is performed so that the pressure ratio PR of upstream side exhaust pressure P3 to downstream side exhaust pressure P4 does not exceed the predetermined pressure ratio PR0, and the final target upstream side exhaust pressure P3CMDF is calculated (S13 to S16). Target vane opening VOCMD is set so that the detected upstream side exhaust pressure P3 coincides with the final target upstream side exhaust pressure P3CMDF (S17, and S18).