To reduce the quantity of a closed package 2 to be discarded by quickly correcting an angular position to a desired axis of a packaging material tube to be bended.

This packaging machine 1 for manufacturing a closed package of liquid food comprises molding assemblies 11, 12, 13, 14 obtained by gradually superposing the side edge parts on both sides of a strip 3 for forming the tube 9, a sealing means 15 for forming a seam (16), in the longer direction, of the tube 9, an actuation device 41 which is actuated and connected to a bending member and rotates the bending member around the axis in the longitudinal direction in order to adjust the angular position of the bending member, a senor means 42 which is arranged on the downstream side of the sealing means and generates a position signal relative to the angular position of the seam and a control unit 43 which receives the position signal and generates a control signal. The control signal is output to the actuation device 41 so that the seam is returned to the desired angular position.