Control device for internal combustion engine

Provided is a control device for an internal combustion engine capable of estimating the amount of gas flowing into a cylinder of the internal combustion engine with higher accuracy than in the prior art. A control device (110) for an internal combustion engine is provided with a mass flux calculation unit (F2), an opening area calculation unit (F3), an effective opening area calculation unit (F4), and a passing gas flow calculation unit (F5). A mass flux calculation unit (F2) calculates the mass flux (MF) of the gas passing through the throttle valve (125) on the basis of the upstream-side gas temperature (Tu), the upstream-side gas pressure (Pu), and the downstream-side gas pressure (Pd) of the throttle valve (125). The opening area calculation unit (F3) calculates the opening area (A) of the throttle valve (125) on the basis of the opening degree (theta) of the throttle valve (125). An effective opening area calculation unit (F4) calculates the effective opening area (EA) of the throttle valve (125) on the