PURPOSE: To keep an arc length to fit to the TIG welding by generating an arc between a tungsten electrode and a base metal by a high frequency electric current and, at the same time, drawing up only the electrode by a needed length automatically.

CONSTITUTION: First of all, a distance (b) between a tungsten electrode 4 and a base metal 11 is shortened to perform welding in a high pressure gas. Then, a welding gone of the base metal 11 and the electrode 4 are shielded with a nozzle 8, and an inactive argon is allowed to flow. An electric power is then supplied to an arc welder and a high frequency current is applied between the electrode 4 and the metal 11, then an arc is generated. Concurrently with the generation of the arc, taking said generation as a signal, a current is applied to an electromagnetic coil 3 to draw up the electrode 4. Thereby, a fixed iron core 1 is energized by the current applied to the coil 3, and a movable iron core 2 is drawn up resisting to a spring 5 by a distance (l). Thus, the arc length is lengthened to g+l, and is made to the arc length which is fit to the welding.