A steering apparatus for a steer by wire system includes a first motor and a second motor configured to provide a torque. A first planetary gear set is configured to receive the torque from the first motor and to generate a reaction torque required for steering. A second planetary gear set is configured to receive the torque from the steering wheel and the second motor, and to variably output a gear ratio for an input by the steering wheel depending on a rotation of the second motor. A stopping mechanism is configured to limit a maximum rotation angle of the steering wheel.