A positive feed picking device for a fluid jet loom includes a yarn measuring and storing device; a main picking nozzle; a positive feed mechanism including a drive roller and a motor for driving the drive roller. The positive feed mechanism is disposed between the yarn measuring and storing device and the main picking nozzle to feed a weft yarn positively to the main picking nozzle during a picking period. The feed picking device also includes a sensor disposed on a yarn path along which the weft yarn travels for detecting the delivery of a predetermined length of the weft yarn from the yarn measuring and storing device. A motor controller for controlling the operating speed of the motor of the positive feed mechanism, and a controller for controlling the positive feed mechanism are also included in the positive feed picking device. The controller starts the positive feed mechanism at the start of picking period. The motor controller controls the motor so that the rotating speed of the motor varies according to a predetermined speed control characteristic.