A control apparatus for an internal combustion engine comprises a throttle upstream pressure estimation unit which calculates, based on an AFS intake air amount from an AFS and an intake manifold pressure, an average density ρave(n) in a region combining a supercharged portion from a downstream of a compressor to an upstream of a throttle valve and an intake manifold, and estimates a throttle upstream pressure based on the intake manifold pressure and the average density ρave(n). Further, the throttle upstream pressure estimation unit learns a relationship between a throttle opening degree and an effective opening area to correct a throttle upstream pressure estimated value (estimated P2) based on a range of a throttle opening degree learning value, the throttle opening degree learning value, and a dispersion of the actual throttle opening degree error.