In a steering apparatus for a ship propeller in which a steering handle is provided within a ship body, a propelling unit is fixed to a steering shaft rotatably supported to an attaching bracket fixed to the ship body. A steering cable connected to the steering handle is coupled to a steering arm fixed to the steering shaft. A motor-driven steering assist apparatus for assisting a steering force applied to the steering handle by a driver on the basis of a torque generated by the electric motor is interposed between the steering handle and the steering cable.