To improve the response characteristic of a feed motor for a length measuring and storing device, and at the same time, suppress the heat generation undesired for the feed motor during driving.

This controller comprises a length measuring and storing device 2 for performing a length measuring and storing operation of weft yarn by the rotation of a feed motor 3, a follow-up controller 7 outputting speed commanding signals following-up the rotation of the main axis of the loom, and a driving controller 8 outputting driving signals to the feed motor based on the speed commanding signals from the follow-up controller 7. The internal storage unit 24 of the driving controller 8 has a plural characteristic data for acceleration and deceleration stored in advance; and at least on the time of either starting up or stopping of the feed motor 3, the datum having a higher (speedier) response speed out of the data for acceleration and deceleration is used for outputting driving signals, and during the stationary driving, the datum having a lower (slower) response speed out of the data for acceleration and deceleration is used for outputting driving signals.