A weft withdrawing device of an air jet loom includes a blow nozzle blowing a weft that is ejected from a weft insertion main nozzle and determined to be a weft insertion failure to guide the weft to a weft withdrawing passage, a weft introducing duct that is integrally swingable with a sley forward and backward, a weft withdrawing mechanism withdrawing the weft guided to the weft introducing duct, and a weft sensor optically detecting the weft. The weft withdrawing device of the air jet loom includes a weft guide member. The weft guide member includes a cloth fell side top portion and a let-off side top portion. The cloth fell side top portion is located above the weft withdrawing passage.