Abstract: When splicing optical fibers by melt-fusioning in an electric arc, the electric arc is started, in order to give the fiber splice a large strength, before the ends of the fibers have entered the arc and before they have contacted each other. The arc is in this stage switched on with a low intensity which is increased in the stage when the fiber ends are fusioned to each other. When the electric arc is established having this low intensity and immediately before the contact of the end surfaces and the melt-fusioning, the fiber ends are finely aligned with each other in the lateral direction. It can be performed by way of the optical system and the controller means which are provided in a commercially available fiber welding apparatus, and the fine alignment will give the splice a low attenuation. For standard fibers of the single-mode type a welding current through the electrodes of approximately 6.5 mA is suitable.