Incidentally, for example, a connector is attached to an end portion of the high frequency signal transmission cable 1. At this point, the end portion of the high frequency signal transmission cable 1 is subjected to a termination to expose the plating layer 4, the insulator 3, and the inner conductor 2 in a staircase pattern. In the present embodiment, since the crack suppressing layer 7 and the insulator 3 are not being adhered or joined to each other, the plating layer 4 and the crack suppressing layer 7 can easily be peeled off from the outer surface of the insulator 3, and the termination can easily be performed.

Also, the plating layer 4 and the inner conductor 2 exposed by the termination are each connected to a substrate within the connector by soldering or the like. When the plating layer 4 is connected thereto by soldering or the like, the plating layer 4 is heated. At this point, for example, when the plating layer 4 is being formed directly on the outer surface of the insulator 3, the insulator 3 is expanded due to heat, and the plating layer 4 is stretched by following the expansion of the insulator 3, which may therefore cause the plating layer 4 to crack. In the present embodiment, even when the insulator 3 is expanded due to heating the plating layer 4, the crack suppressing layer 7 acts to be slid between the plating layer 4 and the insulator 3 without following this expansion of the insulator 3, so there is also merit that the plating layer 4 is resistant to the occurrence of a cracking resulting from thermal expansion of the insulator 3.