Abstract: A leaky cable is provided with a linear insulator and a metal layer formed on an outer peripheral surface of the insulator. A slot for leaking electromagnetic waves is formed through the metal layer between an inner peripheral surface and an outer peripheral surface of the metal layer, and the outer peripheral surface of the insulator is formed with unevenness that inhibits misalignment of the slot with respect to the insulator. The method of manufacturing the leaky cable includes forming an insulator composed of thermoplastic resin in a cylindrical shape, roughening an outer peripheral surface of the insulator, forming a metal layer on the outer peripheral surface of the insulator, and forming a slot through the metal layer between an inner peripheral surface and an outer peripheral surface of the metal layer. The slot is configured to leak electromagnetic waves to outside of the metal layer.