A driver assistance system configured to: receive a target trajectory of a vehicle determined based on driving environment-related information regarding a driving environment ahead of the vehicle, the driving environment-related information being acquired by an external environment recognition part; determine, based on the driving environment-related information, a departure risk (COR L, COR R) of the vehicle departing from a drivable width of a road on which the vehicle travels; determine, as actuator operation variable-related information regarding an operation variable of an actuator related to a steering and/or braking/driving operation that causes the vehicle to travel along the target trajectory, a feedforward operation variable (FY FF) based on a road curvature, the road curvature at least partially constituting the driving environment-related information regarding the driving environment ahead of the vehicle acquired by the external environment recognition part; a feedback operation variable (FY FB) based on a difference between a target position of the vehicle that ensures that the vehicle travels along the target trajectory and a preview position of the vehicle determined based on the driving environment-related information regarding the driving environment ahead of the vehicle acquired by the external environment recognition part; and a vehicle stabilizing moment operation variable (Mst) for applying, to the vehicle, a moment based on the braking operation of a brake device configured to apply a braking force to the vehicle, the brake device at least partially constituting the actuator; downwardly correct the vehicle stabilizing moment operation variable (Mst) in accordance with the departure risk (COR L, COR R), when directions of movement requested by the feedforward operation variable (FY FF) and movement requested by the vehicle stabilizing moment operation variable (Mst) are opposite to a direction of movement requested by the feedback operation variable (FY FB), and a total amount of the movements requested by the feedforward operation variable (FY FF) and the vehicle stabilizing moment operation variable (Mst) is greater than an amount of the movement requested by the feedback operation variable (FY FB); and output the actuator operation variable-related information to the actuator. receive a target trajectory of a vehicle determined based on driving environment-related information regarding a driving environment ahead of the vehicle, the driving environment-related information being acquired by an external environment recognition part; determine, based on the driving environment-related information, a departure risk (COR L, COR R) of the vehicle departing from a drivable width of a road on which the vehicle travels; determine, as actuator operation variable-related information regarding an operation variable of an actuator related to a steering and/or braking/driving operation that causes the vehicle to travel along the target trajectory, a feedforward operation variable (FY FF) based on a road curvature, the road curvature at least partially constituting the driving environment-related information regarding the driving environment ahead of the vehicle acquired by the external environment recognition part; a feedback operation variable (FY FB) based on a difference between a target position of the vehicle that ensures that the vehicle travels along the target trajectory and a preview position of the vehicle determined based on the driving environment-related information regarding the driving environment ahead of the vehicle acquired by the external environment recognition part; and a vehicle stabilizing moment operation variable (Mst) for applying, to the vehicle, a moment based on the braking operation of a brake device configured to apply a braking force to the vehicle, the brake device at least partially constituting the actuator; downwardly correct the vehicle stabilizing moment operation variable (Mst) in accordance with the departure risk (COR L, COR R), when directions of movement requested by the feedforward operation variable (FY FF) and movement requested by the vehicle stabilizing moment operation variable (Mst) are opposite to a direction of movement requested by the feedback operation variable (FY FB), and a total amount of the movements requested by the feedforward operation variable (FY FF) and the vehicle stabilizing moment operation variable (Mst) is greater than an amount of the movement requested by the feedback operation variable (FY FB); and output the actuator operation variable-related information to the actuator.