A packaging and filling apparatus for keeping pressure of filled liquid food in a tube at positive pressure, facilitating preformation by a forming flap, and preventing an external ambient substance from entering the tube even if the liquid food pressure lowers to negative pressure by a fluctuation of the liquid food pressure is described. The apparatus has a pressure flange provided below a liquid level in a tubular packaging material and along an outer periphery of a filling pipe. The pressure flange prevents the liquid food in the tube from freely flowing up from the lower part to keep the pressure of the liquid food positive in the tube below the pressure flange thereby facilitating the preformation by the forming flap. The apparatus closes a gap occurring on a seam serving as a vertical sealed part or a portion where the gap might occur.