An ECU determines whether or not an engine water temperature has exceeded a predetermined value; and actively opens and closes a wastegate valve, and calculates a shift in a learning value amount. The ECU determines whether or not the learning value shift amount is sufficiently large to surpass a predetermined value and when the determination result is Yes (when the condition is fulfilled), takes in the learning value shift. The ECU determines whether or not the engine water temperature is sufficiently low to be below a predetermined value and reflects the learning value shift in the air-fuel ratio learning value.