In a control apparatus for an internal combustion engine, a vapor concentration learned value learned as a concentration of fuel in purge gas is reflected in an injection amount command value used for fuel injection amount control. An electronic control unit changes a reflection mode of reflecting the vapor concentration learned value in the injection amount command value depending on a pattern of switching an inlet through which the purge gas flows into an intake passage, between a first inlet and a second inlet upstream of the first inlet, and executes the reflection in the changed reflection mode during a period from a start of an intake of intermediate gas into a cylinder to completion of the intake of the intermediate gas. The intermediate gas is present in a portion of the intake passage between the first inlet and the second inlet when switching of the inlet is performed.