Abstract: In a very high voltage electrostatic generator, the electrostatic charges are conveyed by a belt which rotates in a closed circuit between the earthed zone and the high voltage zone of the generator. According to the invention, a structure (6) offering a flat surface (60) to the belt section (5) is provided opposite the belt section (5). A gap (50) containing sulphur hexafluoride is thus formed between the structure (6) and the belt section (5). The structure (6) is made of a dielectric material (61) such as an epoxy resin which preferably contains conductive elements (62). The structure (6) is in addition traversed by tubules (63) opening on to the surface (60) so as to enable a cushion of sulphur hexafluoride to be formed in the space (50). This arrangement can operate under higher electric charge outputs than has hitherto been possible.