Abstract text

Upon cutting a corner of a plastic bag, the cut-out portion is prevented from attaching to the plastic bag. A plastic film (1) is trimmed by a trimming cutter (7) to form a selvage (8). Every time that the plastic film (1) is intermittently fed, the trimming cutter (7) is moved by a trimming cutter moving mechanism, so that a corner of the plastic bag is cut by the trimming cutter (7) and the cut-out portion (11) is continued from the selvage (8).