To provide a technology for achieving further stabilization of an untwisting point relative to the intersection of belts, and compaction of a device simultaneously.

A belt type false twister 111 twists a yarn Y while nipping by traveling a reference belt 1 and a movable belt 2 while intersecting and pressure contacting each other. A drive pulley 10 about which the reference belt 1 is entrained is provided with an untwisting disc 50 having an outer circumferential edge 50a. The untwisting disc 50 is constituted to rotate together with the drive pulley 10. Outside diameter D of the untwisting disc 50 at the outer circumferential edge 50a thereof is set equal to or larger than a value obtained by adding the thickness of the reference belt 1 to the outside diameter of the drive pulley 10. The yarn handling area of the yarn Y on the downstream side of an intersection R is bent by contact with the outer circumferential edge 50a of the untwisting disc 50.