To provide a running trouble detecting apparatus to prevent troubles in the case where a repier head is left in a warp opening.

This running trouble detecting apparatus comprises a repier head 11 fitted to a repier band 13 for warp delivery and a repier head 12 fitted to a repier band 14 for repier take-up to meet each other in the warp opening, a band guide 36 that guides running of the repier bands 13, 14, a first runner detector 39 fitted to a band guide 36 in the middle over the looming width, and a second runner detector 40 fitted to another band guide 36. The detection signals generated by the runner detectors 39, 40 are sent to a control computer C1, and the control computer C1 controls a loom driving motor 20 to emergency- stop the loom by the detection signals sent from the runner detector 39, 40.