To provide an abnormality-detecting device capable of detecting the abnormality in detecting function of plural weft yarn sensors arranged in passage for weft yarn insertion.

This abnormality-detecting device 2 for weft yarn sensors is obtained by providing plural weft yarn sensors 22 (23, 24, 38) arranged on weft yarn passages from a length-measuring and storing device 5 on the downstream side of the weft yarn insertion and an abnormality-detecting circuit 29 inputted with detecting signals from at least 2 weft yarn sensors 22 (23, 24, 38) and outputting the abnormality- detecting signal toward the weft yarn sensor when not generating the detecting signal from the other side yarn sensors 22, (23, 24, 38) during a check period set in accordance with any one of inputted detecting signals, and setting the check period set at the abnormality-detecting circuit 29 corresponding to an inputting time of the detected signal from the above one side weft yarn sensors 22 (23, 24, 38), a necessary time to reach from the detecting zone of the yarn sensors 22 (23, 24, 38) arranged on the upstream side for the weft yarn insertion in the normal time for the weft insertion to the detecting zone of the weft yarn sensors 22 (23, 24, 38) arranged on the downstream side of the weft insertion and an allowable range set in accordance with the response delay of the above one side or the other side weft yarn sensors 22 (23, 24, 38).