PURPOSE: To accurately control the heating by attaching a temperature sensor to the exposed surface of a cable insulator and controlling the temperature when heating an oil stopping mold metal fitting, which is arranged around the insulator of a cable terminal, and a layer of a wound seal tape with a ribbon heater, or the like.

CONSTITUTION: An oil stopping metal fitting 4 is set on the insulator 3 of the terminal of a cable 1, and a seal tape 5 is wound. A ribbon heater 6 is wound astride the mold metal fitting 4 and the seal tape 5, and it is heated by electrification from a power source 16. A temperature sensor 21 consisting of a thermocouple is attached to the exposed part of the insulator 3 of the terminal of the cable 1, and the signal is input into the a temperature detecting means 20, whereby the electrification is controlled to control the temperature. Hereby, accurate heating control is performed, and the reliability of the terminal improves.