A device for evacuating gas from a package for a packaging apparatus, the package having an open end, the open end having a terminal portion, a non-terminal portion, and an intermediate portion located between the terminal portion and the non-terminal portion of the open end, the device comprising: a vacuum chamber having an elongated opening extending along a longitudinal axis of the vacuum chamber, an evacuation means configured for providing the vacuum chamber with an internal vacuum pressure that is lower than an ambient pressure outside the vacuum chamber, a means for moving a package relative to the vacuum chamber, and a control unit programmed for: controlling the means for moving to relatively move a package to be evacuated with respect to the vacuum chamber, the package and the means for moving each being arranged with respect to the vacuum chamber so that a main movement direction of packages placed on the means for moving and the longitudinal axis of the vacuum chamber are substantially parallel to one another, the package to be evacuated being positioned so that, during the relative movement of the package with respect to the vacuum chamber, a terminal portion of the open end of the package relatively moves within the vacuum chamber and a non-terminal portion of the open end relatively moves outside the vacuum chamber, an intermediate portion of the open end passing through and relatively moving along the opening, and activating the evacuation means to provide the vacuum chamber with the internal vacuum pressure, wherein the vacuum chamber comprises a first sub-chamber (10-1, 10-2, 10-3) and a second sub-chamber (10-1, 10-2, 10-3), and being characterized in that: the control unit is further programmed to provide the first sub-chamber (10-1, 10-2, 10-3) with a first pressure and to provide the second sub-chamber (10-1, 10-2, 10-3) with a second pressure different from the first pressure. a vacuum chamber having an elongated opening extending along a longitudinal axis of the vacuum chamber, an evacuation means configured for providing the vacuum chamber with an internal vacuum pressure that is lower than an ambient pressure outside the vacuum chamber, a means for moving a package relative to the vacuum chamber, and a control unit programmed for: controlling the means for moving to relatively move a package to be evacuated with respect to the vacuum chamber, the package and the means for moving each being arranged with respect to the vacuum chamber so that a main movement direction of packages placed on the means for moving and the longitudinal axis of the vacuum chamber are substantially parallel to one another, the package to be evacuated being positioned so that, during the relative movement of the package with respect to the vacuum chamber, a terminal portion of the open end of the package relatively moves within the vacuum chamber and a non-terminal portion of the open end relatively moves outside the vacuum chamber, an intermediate portion of the open end passing through and relatively moving along the opening, and activating the evacuation means to provide the vacuum chamber with the internal vacuum pressure, wherein the vacuum chamber comprises a first sub-chamber (10-1, 10-2, 10-3) and a second sub-chamber (10-1, 10-2, 10-3), and being characterized in that: the control unit is further programmed to provide the first sub-chamber (10-1, 10-2, 10-3) with a first pressure and to provide the second sub-chamber (10-1, 10-2, 10-3) with a second pressure different from the first pressure. controlling the means for moving to relatively move a package to be evacuated with respect to the vacuum chamber, the package and the means for moving each being arranged with respect to the vacuum chamber so that a main movement direction of packages placed on the means for moving and the longitudinal axis of the vacuum chamber are substantially parallel to one another, the package to be evacuated being positioned so that, during the relative movement of the package with respect to the vacuum chamber, a terminal portion of the open end of the package relatively moves within the vacuum chamber and a non-terminal portion of the open end relatively moves outside the vacuum chamber, an intermediate portion of the open end passing through and relatively moving along the opening, and activating the evacuation means to provide the vacuum chamber with the internal vacuum pressure, wherein the vacuum chamber comprises a first sub-chamber (10-1, 10-2, 10-3) and a second sub-chamber (10-1, 10-2, 10-3), and being characterized in that: the control unit is further programmed to provide the first sub-chamber (10-1, 10-2, 10-3) with a first pressure and to provide the second sub-chamber (10-1, 10-2, 10-3) with a second pressure different from the first pressure.