A filling packaging machine comprising: a tape attachment device for attaching a sealing tape to one end of one surface of a web-like packaging material such that the sealing tape partly protrudes outside the packaging material in the width direction; a vertical sealing device for vertically sealing both ends of the web-like packaging material such that they overlap with each other by a predetermined width to form a tubular packaging material and to attach a protruding portion of the sealing tape to an inner surface of the tubular packaging material so that it can cover an inner step of the overlapping portion; and a lateral sealing device for laterally sealing the tubular packaging material, filled with contents, at an interval corresponding to the length of one container, the lateral sealing device including an ultrasonic horn and an anvil which are openably/closably provided on opposite sides of the tubular packaging material, and have sealing surfaces facing each other and extending in a direction perpendicular to the length direction of the tubular packaging material, and having an absorption portion, formed in the sealing surface of one of the ultrasonic horn and the anvil, for absorbing steps formed between the overlapping portion and the other portion, characterised in that the tape attachment device attaches a predetermined-width portion of the sealing tape to the one end of the one surface of the web-like packaging material in such a manner that a first edge of both edges of the sealing tape, which is to be located on an overlapping portion side of the sealing tape when viewed from the inner step of the overlapping portion, will be disposed at a position displaced from an outer step of the overlapping portion when viewed in the thickness direction of the tubular packaging material, wherein the tape attachment device attaches a predetermined-width portion of the sealing tape to the one end of the one surface of the web-like packaging material in such a manner that the first edge of the sealing tape will be disposed at a position which is displaced by not less than 0.5 mm from the outer step of the overlapping portion in a direction away from the inner step of the overlapping portion. a tape attachment device for attaching a sealing tape to one end of one surface of a web-like packaging material such that the sealing tape partly protrudes outside the packaging material in the width direction; a vertical sealing device for vertically sealing both ends of the web-like packaging material such that they overlap with each other by a predetermined width to form a tubular packaging material and to attach a protruding portion of the sealing tape to an inner surface of the tubular packaging material so that it can cover an inner step of the overlapping portion; and a lateral sealing device for laterally sealing the tubular packaging material, filled with contents, at an interval corresponding to the length of one container, the lateral sealing device including an ultrasonic horn and an anvil which are openably/closably provided on opposite sides of the tubular packaging material, and have sealing surfaces facing each other and extending in a direction perpendicular to the length direction of the tubular packaging material, and having an absorption portion, formed in the sealing surface of one of the ultrasonic horn and the anvil, for absorbing steps formed between the overlapping portion and the other portion, characterised in that the tape attachment device attaches a predetermined-width portion of the sealing tape to the one end of the one surface of the web-like packaging material in such a manner that a first edge of both edges of the sealing tape, which is to be located on an overlapping portion side of the sealing tape when viewed from the inner step of the overlapping portion, will be disposed at a position displaced from an outer step of the overlapping portion when viewed in the thickness direction of the tubular packaging material, wherein the tape attachment device attaches a predetermined-width portion of the sealing tape to the one end of the one surface of the web-like packaging material in such a manner that the first edge of the sealing tape will be disposed at a position which is displaced by not less than 0.5 mm from the outer step of the overlapping portion in a direction away from the inner step of the overlapping portion.