This machine is designed to manufacture square bottom paper bags without handles from paper roll, and it is an ideal equipment for producing small-size paper bags fast. By implementing steps including paper feeding, tube forming, tube cutting and bottom forming inline, this machine can effectively save labor costs. The equipped photoelectric detector can correct cutting length, so as to ensure cutting precision. The equipped SIEMENS PLC system ensures that the machine can perform quickly and stably. This machine can process very thin paper, as well as produce paper bags very fast, thus this machine is especially suitable for being applied in food industries.