PURPOSE: To make automatic bag making of a bag with pouring port possible easily by a method wherein pouring ports are attached on a tape first, and both ends of a main body tape is joined to form it into a cylindrical shape using this tape with pouring ports, and cross sealing and cutting are performed.

CONSTITUTION: A main body tape 2 is let out from a roll 1, and both ends are pulled closer by a sailor 3, and the main body tape 2 is wound around a pipe guide 4. A tape 6 is let out from a roll 5, and on the way, holes 8 are bored with specified intervals by a punching machine 7. Then, a pouring port with cap 10 is inserted in the hole 8 from the head from a part feeder 9, and the base part 11 of the pouring port 10 is sealed by a sealer 12 around the hole 8. The tape 6 on which the pouring ports 10 have been attached is inserted inside of both ends 2a, 2b of the main body tape 2 wound around the pipe guide 4, and respective ends 2a, 2b are sealed by a sealer 13. The main body tape 2 in which the tape 6 has been inserted descends along the pipe guide 4, and sealing and cutting are performed by a sealer/cutter 14.