Abstract: The first object of the invention is a process for closing or sealing a flexible tube filled with a liquid, creamy or semi-pasty product (7), in which its skirt (2) is nipped below its open end so as to bring about a closure (10) allowing the escape of the air contained in the tube when the latter is transversely compressed and then after compression the closure (10) is transformed into a tight closure and the open end (17) of the tube is sealed. According to the invention, skirt (2) is nipped with elastically tightened parallel surfaces (10) and the skirt (2) is compressed to the right of the product contained (7), in such a way that the upper level of said product (7) remains below or at the lower limit of closure (10) and the end portion (17) of the tube (1) passing beyond said closure (10) is sealed, so as to avoid any pollution by the product deteriorating the seal. The second object of the invention is an apparatus for performing this process.