An apparatus for distributing particulate material on a conveyor movable along a respective operating direction includes: a tank containing particulate material and equipped with feed means for feeding the particulate material and distribution means located downstream of the tank to receive the particulate material and the particulate material on the conveyor. The distribution means include a diffuser element and a vibrating device to shake the diffuser element. The diffuser element extends with its sliding plane along its axis between an infeed portion to receive a preset flow quantity “Q” of particulate material, and an outfeed portion. The diffuser element includes a transversal partition at a predetermined distance from the sliding plane to form a neck which acts in combination with a vibration imparted by the vibrating device to distribute the particulate material along a predetermined width of the outfeed portion.
