A cable-type steering device for controlling operation of a power-steering motor in accordance with the tension on stranded metal wire cables which connect a vehicle steering wheel to a steering gearbox. Tensions of the cables are detected by contact with an arm of a potentiometer. The surfaces of the cables are smoothed by a swaging treatment or resin coating treatment to prevent undesirable vibrations of the arm of the potentiometer and improve the detection accuracy of the potentiometer. The smoothing treatment eliminates undesirable vibration which might otherwise occur due to irregularity of the surface of untreated stranded metal wire cable.