PURPOSE: To extrude evenly mixed resin to cover a cable by preventing an additive in the resin for extrusion in a cable extrusion covering device from being unevenly mixed in the resin.

CONSTITUTION: A resin channel adjusting device 1, having a group 4 of center round holes and a group 5 of outer periphery round holes both provided through the inlet surface 2 thereof and groups 6, 7 of radially opening crown-shaped oblong holes provided through the outlet surface 3 thereof, is installed on the breaker-plate side portion of a cable extrusion covering device, the group 4 of center round holes and the group 5 of outer periphery round holes of the inlet surface 2 being communicated with the respective groups 6,7 of oblong holes in the outlet surface 3. Therefore, even if resin is extruded with an additive concentrated at the center of the extruded resin on the peripheral surface of an extruder screw, when coming out of the resin channel adjusting device 1 the center part of the resin where the additive is concentrated and the outer peripheral part of the resin where there is a smaller amount of additive are evenly mixed together and extruded to cover a cable.