The plating layer 4 together with the metal shield layer 5 constitutes the outer conductor 8. As described above, although the metal shield layer 5 is configured by braiding or side by side wrapping with the metal wires, the use of only the metal shield layer 5 may lead to internal signal radiation from the spaces between the metal wires to the external side, and therefore an increase in the amount of attenuation. By providing the plating layer 4, the spaces between the metal wires of the metal shield layer 5 are impregnated therewith, and the amount of attenuation is therefore further reduced. Note that the plating layer 4 and the metal shield layer 5 are in contact with each other and are electrically connected together.

As the plating layer 4, the plating made of a metal having an electrical conductivity of 99% or more (99% IACS or more) may be used, and e.g., a metal made of copper or silver can be used.

The thickness of the plating layer 4 may be 2 μm or more and 5 μm or less. When the thickness of the plating layer 4 is 2 μm or more, even with the metal shield layer 5 and the plating layer 4 being in contact with each other and being subjected to a bending, the plating layer 4 is resistant to the occurrence of a cracking. Further, when the thickness of the plating layer 4 is 5 μm or less, it is possible to prevent the high frequency signal transmission cable 1 from becoming difficult to bend due to the plating layer 4 becoming hard.