A controller for an internal combustion engine includes an intake air amount obtaining unit, an open-closed determination unit, and an air bypass valve control unit. The intake air amount obtaining unit is configured to obtain, using a target torque of the internal combustion engine, a target throttle passage amount as a target value of an amount of intake air drawn through a throttle valve. The open-closed determination unit is configured to determine whether a valve opening condition for first and second air bypass valves is satisfied. The air bypass valve control unit is configured to open the first and second air bypass valves when the valve opening condition is satisfied. The open-closed determination unit is configured to determine that the valve opening condition is satisfied when a decrease speed of the target throttle passage amount is greater than a specified determination speed.