To provide an air jet loom designed to markedly reduce energy consumption in weaving operations by the aid of a technical means for raising the weft carriage capacity of an auxiliary nozzle.

This air jet loom has an auxiliary nozzle having the function to issue auxiliary air stream against a guide groove on the front face of a reed, wherein the reed has a 1st dent group specifying a groove section most stringently, a 2nd dent group specifying the lower part of the groove section most loosely, and a 3rd dent group specifying the groove section with such stringency as to be intermediate between those for the 1st and 2nd dent groups; the 2nd dent group is disposed downstream in the weft running direction for the 1st dent group, while the 3rd dent group downstream in the weft running direction for the 2nd dent group; furthermore, the 2nd dent group stands against the auxiliary nozzle, and the guide groove part formed by the 3rd dent group is continuously altered in such a direction as to make cross section specification more stringent from the upstream side in weft running direction toward the downstream side.