PURPOSE: To perform cut line treatment assuredly by arranging a brush roll having an axis in parallel with an axis of a rotary blade so as to come into contact with pressure a blade protrusion of the rotary blade and passing an oriented film between the rotary blade and the brush roll.

CONSTITUTION: At each blade protrusion 2a of a rotary blade 2, a height of a blade from the center to the tip of the blade protrusion is uniform ranging over the whole length of the blade protrusion. The rotary blade 2 is arranged on an axis 5 at regular intervals. An axis 6 of a brush roll 3 is arranged in parallel with the axis of the rotary blade 2. The brush roll 3 is pressed to the blade protrusion 2a of the rotary blade 2 by a required pressure. A plurality of rotary blades 2 are heated by a heater 4. An oriented film 7 is passed between the rotary blade 2 of a film cutting device 1 and the brush roll 3. A large number of cut lines 8 of staggered patterns are made in the oriented film 7 so as to produce a cut line film 9. The cut line film 9 is taken up by enlarging the width. An obtained web 10 is used for weft group so as to produce a stuck piece 11 of warp group and the web 10.