Abstract: A twister for orthodontic ligature wires which easily enable a twisting operation of the wire with one hand, and is capable of clamping the wire with certainty, and simple in construction. The twister for passing the ligature wire in a nipping cylinder and a gripping cylinder to nip the wire, comprises a guide hole provided in the nipping cylinder to enable inserting the wire in a direction along a central axis of the nipping cylinder, an insertion port provided at a tip end of the guide hole, a compartment pin for inhibition of twisting provided on the insertion port, or an engagement piece provided on an extension of the insertion port, and a locking mechanism mounted in the nipping cylinder and the gripping cylinder to allow engagement and disengagement of the wire with one hand.