A selection machine and process for fine particulate material such as, for example, semolina wheat or other food or industrial products in powdery or granular form, where the particulate material is distributed on a continuous mobile support, is transported from the support to a scanning station for the identification in the particulate material, of undesirable parts thereof, and their position on the support, and, subsequently, to a sorting station having a photoconducting element that can be moved in synchronism with the support and on which photoconducting element is formed a latent image of electrostatic charges, corresponding to the position of the undesirable parts, which electrostatic charges separate the undesirable parts from the desired particulate material by electrostatic attraction.