The invention concerns a device and a method to form the split selvedge in a loom, in which the device comprises independent motor means controlled by a central processing unit of the loom on the basis of the actual weaving parameters of each single weft, thereby varying the moment of mutual shifting of the selvedge yarns. It is thus possible to equalize the final tension level of the single wefts, independently from the weaving conditions and from the characteristics of the single weft being inserted, thereby obtaining, after cutting of the split selvedge, a fringe of uniform length even for fabrics woven with different wefts.