A process for manufacturing an electric cable. In particular, the process includes the steps of: a) feeding a conductor at a predetermined feeding speed; b) extruding a thermoplastic insulating layer in a position radially external to the conductor; c) cooling the extruded insulating layer; and d) forming a circumferentially closed metal shield around the extruded insulating layer. The process may be carried out continuously, i.e., the time occurring between the end of the cooling step and the beginning of the shield forming step is inversely proportional to the feeding speed of the conductor.