The present invention relates to: a method, in which a device having a predetermined area, formed like a protective film, is located on a surface of a beverage, such as a soft drink, juice, champagne, beer, or liquor, which is in contact with air, so as to reduce the area of the surface of the beverage that is in contact with the air, thereby delaying spoilage of the beverage and the device can also delay the escaping of a material such as carbonic acid gas or alcohol, which is dissolved in the beverage, from the beverage and the device therefor. Particularly, the disclosed method and device therefor, provided by the present invention, are a useful invention providing high compatibility, which can be implemented without deforming an existing container or stopper and can also be implemented without a big restriction in the appearance, material, or quality of the material of the existing container. Further, the method and device therefor are a useful invention, which allows advertising copy having various characters or patterns to be inscribed on an outer surface included in a device embodied by the present invention, so that it can be expected to have an advertisement effect, and which allows a predetermined space to be formed in the device, thereby securing a separate space, which can be utilized for various uses, in a container.La présente invention concerne : un procédé, dans lequel un dispositif dune taille prédéterminée, réalisé sous la forme dun film protecteur, est placé sur une surface dune boisson, telle quune boisson non alcoolisée, du jus, du champagne, de la bière ou de lalcool, qui est en contact avec lair, de façon à réduire la taille de la surface de la boisson qui se trouve en contact avec lair et à retarder ainsi la détérioration de la boisson, et le dispositif peut également retarder la dissipation dune substance, telle que de lacide carbonique ou de lalcool, qui est dissoute dans la boisson et également le dispositif correspondant. En particulier,
