The invention relates to a jet-weaving machine, particularly an air jet-weaving machine, which comprises a main discharge nozzle (1) with a mixing tube (2) for introducing a weft thread (3) into a shed by means of a conveying fluid discharged from the main discharge nozzle (1), and comprises a clamping device. This clamping device is placed inside the mixing tube (2) in the area from which the weft thread exits, and is provided with an actuator, which is situated outside of the mixing tube (2) and with a lever that is connected thereto in such a manner that this lever, when actuating the actuator (6) via an actuating means or when the actuation is stopped, executes a tilting motion whereby clamping the weft thread in an opening of the mixing tube between itself and an abutment (9).