To constitute an electrode unit comprising a carbon electrode as no loosing may arise between each components of the electrode unit, or a high bonding force is given in the electrode unit, and a measurable loosening torque between the electrode components is increased.

The electrode unit comprising carbon or graphite is constituted by the thread fastening of individual components such as an electrode and a nipple. The component has a contact face that is given an oriented structure. Squamous uplifts that are given an oriented structure are protruded through whole ideally formed contact face in a height of 1 to 100 μm. A pressure of 0.1 to 80 N/mm2 is given to the adjacent contact face of a thread junction.