A singulator device for standard postal objects and extended postal objects, configured for receiving at input groups of standard/extended plane rectangular postal objects grouped in packs and supplying at output singulated standard/extended postal objects, i.e., each one is physically separated from the others. The device comprises: a singulator system; a resting surface for the packs of postal objects; and a drawing system that displaces the packs towards the singulator system, designed to withdraw individually the postal objects that form a front end face of the pack. Also provided is a supporting device, configured for providing abut surfaces on opposite end portions of the packs formed by extended postal objects to keep the extended postal objects with planes of lie substantially perpendicular to the direction of advance, thus preventing the extended postal objects from possibly bending towards the adjacent packs formed by standard postal objects.