A photo film cassette has a spool on which photo film is wound. A cassette shell contains the spool in rotatable fashion. A pair of light-trapping ribbons are respectively mounted inside a photo film passage port in the cassette shell, and prevents ambient light from entering the cassette shell through the passage port. The ribbons are constituted of warp pile fabric woven in a needle loom from warp threads, weft threads, and warp pile threads. A first one of the weft threads is passed under a first one of the warp threads, then passed over a first one of the warp pile threads, and subsequently passed under a second one of the warp threads. The pile fabric is woven so as to symmetrize the first and second warp threads relative to the first warp pile thread. It follows that the ribbons are woven to have the firmly retained warp pile threads that are difficult to drop away from the ribbons.