To provide a bag-forming and packaging machine capable of preventing a developed influence of the fall-down of a vertical seal section from reaching the vertical seal section in a vertical heat-sealer and a side edge even though the already-formed vertical seal section falls down in an inclined state when forming a cylindrical packaging material.

When the vertical heat-seal section 52 formed of the vertical heat-sealer 15 is fed from the vertical heat-sealer 15, a regulation member 20 is arranged to prevent the fall-down of the vertical heat-seal section. When the vertical heat-sealer 15 intermittently performs closing operation accompanied by to the intermittent operation of the bag-forming and packaging machine 10, the vertical seal section 52 and the side edge are properly sandwiched by the vertical heat-sealer 15 so that the vertical seal section 52 and the side edge as a non-sealed section positioned in the vertical heat-sealer 15 are in erecting states. Consequently, the vertical seal section 52 is prevented from being vertically heat-sealed while the vertical seal section 52 falls down, and formed while the vertical seal section 52 is neatly connected with the already-formed vertical seal section.