A flat cable (100) includes plural wires (10), an insulative layer (20) enclosing the wires, a metal shielding layer (30) enclosing the insulative layer, and a jacket (40) enclosing the metal shielding layer. The wires include plural pairs of differential wires (11) for transmitting high speed signals. The pairs of differential wires are evenly arranged in two rows, and each pair of differential wires is axially symmetrically arranged in the up and down direction.