To obtain a weft conveying nozzle having a decreased resistance of air flow pass caused by a contact of the weft with the surface of the peripheral wall.

A helical convex 20 is formed on the inner surface of the peripheral wall of a tubule 162 which constitutes the accelerating tube 16, and on the outer surface of the peripheral wall of the tubule 162 a helical groove 21 is formed. The helical convex 20 and the helical groove 21 are opposed to each other interpasing the wall of the tubule 162 between them, the helical convex 20 and helical groove 21 are circling in the circumferential direction of the tubule 162. The helical groove 21 is a surface imprint formed on tubule 162 from outer periphery to inner periphery, and the helical convex 20 is a trace of a plastic deformation corresponding to the prescribed surface imprint on the inner peripheral wall.