Abstract: An apparatus for controlling coating weight on a steel strip in a continuous hot dip galvanizing process, in which the coating weight is controlled through air wiping after the steel strip passes through a molten zinc coating bath. More particularly, the apparatus keeps the steel strip equidistant from each air knife, uniformly distributes a spray pressure of the air knives in a widthwise direction of the steel strip, and minimizes variation in coating weights on both surfaces of the steel strip. Furthermore, when two steel strips that are different in thickness are continuously hot dip galvanized, the apparatus predicts the movement of the passing line of the steel strips and accurately controls the positions of the air knives. As a result, product deficiencies such as insufficient coating can be reduced and zinc loss due to excess coating can be minimized.