A auxiliary nozzle of an air jet loom includes a nozzle hole formed through a front wall of the auxiliary nozzle and having an inner opening opening to inside of the auxiliary nozzle and an outer opening opening to outside of the auxiliary nozzle. An axis extending in longitudinal direction of the auxiliary nozzle through axial center of the auxiliary nozzle is defined as center axis. An axis intersecting with the center axis and extending in a direction perpendicular to the front wall is defined as weft insertion axis. An axis extending through center of the inner opening and center of the outer opening is defined as nozzle hole axis. The nozzle hole axis is angularly spaced horizontally from the weft insertion axis. Weft insertion is accomplished by compressed air injected from the nozzle hole. The center of the inner opening is positioned on the weft insertion axis.