A time point t0 represents a time point when a turbocharged engine is brought into a decelerating state, and an opening degree of a throttle valve is decreased. A time point t1 represents a time point when an opening command to an ABV is issued. When the ABV has an abnormality, and when a WGV is stuck open, a turbocharging pressure before the time point t0 shows a tendency to fall below a target turbocharging pressure, and a turbocharging pressure after the time point t1 reduces slowly to approach a predetermined pressure. When the WGV is stuck closed, a turbocharging pressure before the time point t0 shows a tendency to exceed the target turbocharging pressure, and the turbocharging pressure after the time point t1 reduces with vigor to approach the predetermined pressure.