A device installed between a surface of a coating bath and an air knife equipment to produce a hot dip metal coated steel sheet to form a non-oxidation atmosphere in a surface of a coated steel sheet ascending from the coating bath, the device comprising: lower gas discharge bars spaced apart from the surface of the coating bath by a predetermined distance and discharging a non-oxidation gas in a direction of the surface of the coating bath along the surface of the coated steel sheet; a side cover extending upwardly slopingly in a direction of the coated steel sheet from the sides of the lower gas discharge bars; and upper gas discharge bars formed at an upper end of the side cover and discharging a non-oxidation gas downwardly.