Device for monitoring threads on a textile machine

A device for monitoring threads on a textile machine, in particular a warp system, with a monitoring needle (19) which rests on the thread (5) in the operating position, is mounted on a shaft (21) running transverse to the thread direction, and is pivotable in the case of a thread breakage from the operating position to an alarm position, in which case a control signal is triggered, characterised in that on one side of the thread path is mounted a light receptor (16) and on the other side a light emitter (17) directed at the receptor, and in that the light beam (29) emissible by the light emitter runs through the plane of the thread and through the pivotal range of the monitoring needle (19) between the operating position and the alarm position, the control signal being capable of being triggered by an irregularity in the thread in the plane of the thread or by the pivotal movement of the monitoring needle (19).