Steering system for vehicle

A steering system for a vehicle, comprising:

• an operation member operable by a driver;
• a front-wheel steering device to which the operation member is connected to enable a front wheel to be steered by a steering amount corresponding to an operation amount of the operation member, the front-wheel steering device including a drive source to apply a steering force to the front wheel;
• a rear-wheel steering device configured to steer a rear wheel independently of the front wheel;
• and
• a controller configured to control the front-wheel steering device and the rear-wheel steering device,
• wherein the controller is configured to execute a front-wheel steering force application control to apply, to the front wheel, the steering force that includes, as a component thereof, a driving support force that causes the vehicle to travel along a target travel line, by controlling the front-wheel steering device, and
• wherein the controller is configured to determine, in the front-wheel steering force application control, the driving support force based on (a) a target operation amount that is the operation amount of the operation member to cause the vehicle to travel along the target travel line and (b) an actual steering amount of the rear wheel or a steering amount of the rear wheel estimated from the target operation amount.