Signal transmission flat cable

A signal transmission flat cable comprising:

• one or more signal conductors comprised of a metallic thin film that extend on a plane in parallel to one another in the cable-length direction;
• a plurality of ground conductors comprised of a metallic thin film that are arranged on both sides in the cable-width direction of the signal conductors;
• an electrically insulating substrate on which the signal conductors and the ground conductors are layered;
• an upper electrically insulating thin-film layer and a lower electrically insulating thin-film layer that cover the signal conductors, the ground conductors, and the electrically insulating substrate from above and below in the cable-thickness direction;
• and
• a protective shielding layer comprised of a metallic layer and an electrically insulating plastic layer to surround the outer periphery of the upper and lower electrically insulating thin-film layers such that the metallic layer is located inside and the electrically insulating plastic layer is located outside;
• wherein the protective shielding layer surrounds the outer periphery with one end edge and the other end edge thereof abutting against each other along the cable-length direction, and the abutting part formed by abutting both the end edges of the protective shielding layer is located above the ground conductor.