A signal transmission cable includes a signal line, an insulation layer configured to cover the signal line, and a plating layer configured to cover the insulation layer. An arithmetic average roughness Ra of an outer peripheral surface of the insulation layer is between 0.6 μm and 10 μm inclusive. A method of manufacturing the signal transmission cable includes covering the signal line with the insulation layer, followed by conducting a dry-ice-blasting on the outer peripheral surface of the insulation layer, followed by conducting a corona discharge exposure process on the outer peripheral surface, and forming the plating layer on the outer peripheral surface.