A thresher head of a harvester has a rotor rotating in the opposite direction to the progress of the machine and holding thresher teeth alignments through which grains are pulled. The rotor is a hollow cylindrical body associated with a command arrangement producing an independent rotary movement in the same direction as the rotor rotation. An axial concentric take air from the ends to generate a flow towards the rotor wall, the fan being associated with the command arrangement A flow channel between the rotor and the axial fan has a face covering more than half of the cylindrical curvature of the rotor, leaving a lower opening that receives the air flow. The hollow rotor holding the thresher teeth rotates at a lesser speed in the same direction as the axial fan.
