To produce a standing bag efficiently, and set a packaging machine in a small setting space.

An upper sealing unit 20 for heat-sealing mating surfaces of a cylindrical film 1 is disposed below a bag-making guide 12 for forming a sheet like film 1a into a cylindrical shape. A bottom sealing unit 40 for heat- sealing top ends of two lugs formed on the cylindrical film 1 by a folding part 30 is disposed on the side opposite to the upper sealing unit 20 with the cylindrical film 1 therebetween. A feed roller 14 for feeding the cylindrical film 1 downward is provided at a position below both the upper sealing unit 20 and the bottom sealing unit 40, respectively, and a lateral sealing unit 50 for heat-sealing the cylindrical film 1 in the horizontal direction is disposed at a position further below the feed rollers 14.