An automatic balancing valve is described, wherein a flow controller device is provided and comprises at least translationally movable plug and a respective valve seat that cooperates with the plug in order to automatically adjust the fluid flow rate through the valve. A ring nut, combined with the flow controller device, is rotationally hand-operated to move a choking member placed inside the valve. The movement transmission from the ring nut to the choking member is achieved by a mechanism comprising a plurality of toothed gears.