PURPOSE: To facilitate tension balance between warp yarn groups of different kinds by unwinding warp yarns from warp yarn bobbins, directly doubling the yarns without winding around a beam, doubling the resultant warp yarn group with a warp yarn group unwound from a warp yarn beam as the other and weaving the yarn groups.

CONSTITUTION: Yarns unwound from warp yarn bobbins without winding around a beam are directly doubled to provide a warp yarn group. Respective suitable tension is applied to the above-mentioned warp yarn group and a warp yarn group wound around a beam as the other to balance the tension. Both yarn groups are then woven.