Abstract: An arc welding machine using non-consumable electrode comprises a welding head the body of which accommodates two non-consumable electrodes arranged at an angle to a passage formed therein and intended for a filler wire to extend therethrough. The welding head is operably connected with a mechanism enabling its vertical movement, and with an electrode oscillating mechanism, the former and the latter being electrically connected to an arc length stabilizer and arc length control device, which, in turn, are connected with a sensor means for sensing angular position of the non-consumable electrodes. Electrically connected to the non-consumable electrodes is a mechanism intended for reversing longitudinal motion of the welding head.