Abstract: A weft picking system for an air jet loom is provided with a microcomputer as a controller. The weft picking system comprises a weft traction device including a pair of rollers, one of which is driven by an inverter motor. A weft yarn fed from a weft measuring and storing device can be placed between the rollers to be drawn toward a weft posture regulating nozzle. The weft posture regulating nozzle is arranged to project the weft yarn into the shed of warp yarns and regulates the posture of the weft yarn under the influence of air jet ejected from the nozzle and from a plurality of sub-nozzles. The rollers always rotate during a weaving operation of the loom. A change-over device is provided to change the weft yarn from a first state of being placed between the rollers to a second state of separating from the rollers or vice versa.