A process for manufacturing a gas-filled multiple glazing unit including at least two glass sheets, the process including a preassembly step in which each glass sheet is positioned inclined at an angle strictly greater than 0° and less than or equal to 10° to the adjacent glass sheet, so as to form at least one cavity, each cavity being completely closed on one of its sides; a step of partially blocking at least one of the sides of each cavity; a step of filling each cavity with gas via an injection side of the cavity; and a step of pressing the glass sheets. One or more cavities of a multiple glazing unit can be filled while reducing the amount of gas used and the filling times.