A device for inserting of weft threads in an air jet weaving machine comprising at least one set of main nozzles (13, 14) which are mounted in series, and to which individual regulating valves (21, 22) are assigned, is provided with a control and regulating unit (17) which defines the individual settings of the regulating valves (21, 22) with respect to one another, in order to form an overall value for the intensity of the impulse transmission of the set of main nozzles with each regulating valve contributing a proportion of the overall impulse intensity.