A warp stop motion device of a weaving machine has upper and lower supports respectively for contact bars and guide bars lying in transversely spaced vertical planes with vertically extending legs thereon having adjustment and locking means to facilitate a clamped vertical adjustment between the upper and lower supports. The lower supports are cantilevered at one end to a longitudinally extending beam serving as a warp end carrying support, and the upper supports are cantilevered at one end to the one end of the lower supports. Thus, the opposite ends of the upper and lower supports are free and unsupported for the reception of the guide bars from such ends during assembly.