A composite insulator comprises a rod with an insulating jacket and ribs and at least one end fitting and at least one corona shield. The latter is integrally manufactured from plastic material. It is configured to be coaxially disposed on the composite insulator at the transition from the rod to the end fitting. The corona shield forms a cavity, which is open towards the inside and which can be filled with sealant compound through at least one filling channel and which comprises a closing cuff in axial direction on both sides for sealing the cavity. The diameter of the rod side closing cuff is adapted to the diameter of the insulating jacket, and the diameter of the fitting side closing cuff is adapted to the diameter of the end fitting. The filling channel leads to the cavity from the outside.