An extrusion device for making spiral stripping electrical wires is disclosed to include a fixed mold member, which has a main flow path and a supplementary flow path for the passing of a first insulative material and a second insulative material, and a rotating mold member, which is rotatably supported on the front end of the fixed mold, having a mold hole axially connected to the outlet of the main flow path and one or multiple flow paths, each flow path of the rotating mold member having an outlet in communication with the mold hole and a common annular inlet disposed in communication with the outlet of the supplementary flow path for guiding the second plastic material spirally into the first plastic material to form a spiral strip in the insulator during extrusion of the two plastic materials with a conductor through the mold hole.