To provide the manufacturing device for a packaging bag, the cost of installation of which is low, and the cutting property of which is favorable, and which can surely manufacture a packaging bag with a predetermined shape, and to provide its method and the packaging bag.

A cutting device 370 is equipped with a male blade 371, a female blade 372, a movement control part 373 and a sucking device 374, The male blade 371 has a rectilinearly cutting part 3711 formed rectilinearly with a certain thickness at its central portion, round-cut parts 3712 in each of which a nearly planar arc-shaped round (R) is formed in a plane shape in continuous with the rectilinear cutting part 3711, and ends 3713 each of which is formed adjoining the round-cut part 3712. The female blade 372 has an opening formed in the same shape as a plain view of the male blade 371 and has a fitting part 3721 to which the male blade 371 is fit. Further, at each side of the female blade 372, a hole in a continuous form through which a base material film penetrates from one side to the other side of the female blade is formed as an penetration part 3722.