A steer-by-wire control device according to the present invention includes a control device that controls a first motor that operates a steering wheel of a vehicle and a second motor that controls steering operation of a wheel. Before making a transition to an automatic driving mode of the vehicle, the control device applies input torque to the steering wheel by the first motor in a forward rotation direction and a backward rotation direction of rotation directions of the first motor, acquires behavior information of the steering wheel obtained by application of the input torque, and determines whether or not to estimate a control parameter of the steering wheel based on the behavior information. The behavior information includes at least one of a value of a rotation angle of a steering wheel and a value obtained by time-differentiating a rotation angle.