PURPOSE: To obtain an air jet loom capable of constantly retaining weft throughout the insertion pass by installing a stretching device on the upstream of a cramping device in the weft inserting direction outside of a reed, stretching and straining the weft threads retained in the cramping device, forming a loop of the weft threads.

CONSTITUTION: This air jet loom installs the stretching device 13 between the cramping device 10 which retains weft threads 3 until driving to a reed, and a stopper 9 for weft movement. The stretching device 13 forms a loop of weft threads for it stretches and strains the weft threads 13 between cramping device 10 and nozzle 2, e.g. throughout the insertion channel.