A cotton picking machine comprises a chassis for moving the machine in a traveling direction, a vacuum pump provided to create a predetermined vacuum and a cotton picking unit including a cotton picking head supported by the chassis. The cotton picking head includes upper and lower vacuum compartments both in fluid communication with the vacuum pump and connecting tubes vertically extending between the upper and lower vacuum compartments and movable along a predetermined endless path so as to be in sliding contact with the upper and lower vacuum compartments at the corresponding distal ends thereof. Each of the connecting tubes includes a set of hollow picking fingers radially outwardly extending therefrom. The predetermined endless path includes an extracting zone and an inoperative zone. The connecting tubes fluidly connect the upper and lower vacuum compartments only when the connecting tubes pass the extracting zone of the predetermined endless path.
