A method of and an apparatus for selectively releasing a predetermined length of weft thread in shuttleless looms, wherein a separating wheel provided with a control on the periphery thereof, having unequal heights or angular spacings, displaces a winding of weft thread, having an insertion length and wound in a space between two controls, in the direction of withdrawal of the weft thread, along a supply drum comprised of segments and always releases at least one complete insertion length of weft thread into the warp shed at a time period determined by a weft thread releasing program.