STEERING ASSIST DEVICE

In a steering assist device, a lane keep assist current value calculation unit 51 calculates, based on a lateral deviation y and a lateral deviation change rate dt/dt, a lane keep assist current value Ir4* that makes the lateral deviation y and the lateral deviation change rate dy/dt closer to zero. When the steering direction represented by the sign of control steering torque Ts is the same as the steered direction represented by the sign of the fourth lane keep assist current value Ir4*, a switch unit 53 selects zero received at its second input terminal and outputs zero as a final lane keep assist current value Ir*.