The invention concerns a device for applying to one side of a lens a coating film (63) that has been pre-deposited on the side of the lens in question, said device comprising a seat (40) capable of receiving the lens, a membrane (62) comprising a peripheral retaining part (62A) and an inflatable part (62B), and means (61) for inflating the membrane in the direction of the lens seat. According to the invention, the inflating means comprise a first plate (66) and a second plate (65) between which the membrane is placed, the first plate having a recessed pressurization chamber (80) connected to a source of compressed gas (93) and the second plate having a protruding opening (71), both plates being mounted so as to be movable relative to each other between an open configuration and a closed configuration.