The crack suppressing layer 7 serves as a foundation layer for the plating layer 4, and when the high frequency signal transmission cable 1 is bent, the crack suppressing layer 7 acts to suppress the occurrence of a cracking in the plating layer 4 resulting from the bending of the insulator 3 following the bending of the high frequency signal transmission cable 1. In other words, the crack suppressing layer 7 is a layer to suppress the occurrence of a cracking in the plating layer 4 by bending while moving in the longitudinal direction of the cable 1 relative to the bending of the insulator 3. Note that the “cracking” referred to herein refers to a cracking in the plating layer 4 that occurs in a range from the outer surface of the plating layer 4 to the inner surface of the plating layer 4 (the surface in contact with the insulator 3). Further, the “suppress the occurrence of a cracking in the plating layer 4” referred to herein refers to making the plating layer 4 resistant to the occurrence of a cracking, as compared to when the crack suppressing layer 7 of the present embodiment is not provided.