Paper bag machine series is applied to produce many types of paper bags such as food paper bags, shopping bags and so on. This machine can produce paper bags of varying sizes at a high speed, thus is especially suitable for being applied in food and clothing industries. It is side gluing, roll folding, roll paper cutting, bottom folding, bottom gluing, bottom forming, bag out in one line. It is easy to operate, highly efficient, and stable, thus it effectively saves labor costs. The equipped photoelectric detector can also correct cutting length, so as to ensure cutting precision.