A
polymer jacket tube includes a conductor bar 1 which has a conductor
insertion hole 1a at its lower end part, a rigid insulation sleeve 2 which is provided at the outer periphery of the conductor bar 1, and a
polymer covering 3 which is provided at the outer periphery of the insulation sleeve 2. The insulation sleeve 2 includes a large-
diameter insulation sleeve 2a which is provided at the outer
peripheral part of the lower portion of the conductor bar 1, and a small-
diameter insulation sleeve 2b which is provided at the outer
peripheral part of the portion of the conductor bar 1 except the distal end part thereof, and an embedded
metal fitting 4 for electrical
stress relief is buried in the continuous portion of the large-
diameter insulation sleeve 2a and the small-diameter insulation sleeve 2b. Besides, a cone-shaped reception port 5 which receives the stress cone 12 of a cable terminal 11 is provided at the lower end part of the large-diameter insulation sleeve 2a, and this reception port 5 is held in communication with the conductor
insertion hole 1a of the conductor bar 1.