PURPOSE: To provide a detector designed to identify warp break position along weave width on an interval basis and enable a warp repair after break detection to be made quickly.

CONSTITUTION: In a yarn break detector 1 made up of warp hooking members 3 arranged in parallel along weave width and a rotator 2 having a wire material 4 stretchedly set along weave width, plural guides 17 are formed along the rotator 2's axial direction and their respective tips are brought to close proximity to the wire material 4, and their mutual contacts are made detectable each two of the guides 17 adjacent to each other by a sensor 21, and when a contact occurs, the result is outputted as the position signal corresponding to such a pair of guides 17.