Provided is a steel strip stabilizing apparatus which dampens vibrations of a plated steel strip in a non-contact manner or corrects the shape of the plated steel strip. The steel strip stabilizing apparatus comprises: a plurality of steel strip damping means arranged on at least one side of a steel strip undergoing processing in a direction there towards so as to damp vibrations in the steel strip; and a damping means moving unit connected to the steel strip damping means to move at least a portion of each of the steel strip damping means in a widthwise direction with regard to the steel strip corresponding to the width of the steel strip. According to the present invention, (unit) damping means are movable in the widthwise direction with regard to the steel strip, thus improving the vibration damping properties, the steel strip curvature correcting properties and the plated quality of the steel strip.