To provide a method for filling a filling machine for a paper container with a web packaging material without such a trouble that in the filling machine, a sealing failure occurs in the lengthwise line sealed part of a paper- joined part and a burst breaks out at a spot where the sealing failure occurs, even when the paper-joined part is included in the midpoint of the packaging material.

The generation of a burst during a filling step is prevented from being experienced by arranging a notch near the corner parts of the forward and rear ends of the web packaging material of a foil having an electromagnetic nature, during a paper joining step for fixing the forward end of the web packaging material to be used next to the rear end of the web packaging material in the process of manufacturing the paper container in order to continuously operate the filling machine.