A method for manufacturing a device for dispensing a product, including a supply of a device having a reservoir, the reservoir being connected to a deformable chamber and being provided with a filling opening, the interior of the deformable chamber being delimited at least in part by a movable wall, a displacement of which causes a variation in the volume of the deformable chamber, a step of filling of the chamber deformable through a filling valve, a step of filling of the reservoir with product, and a closing step in which the filling opening is closed. Application includes, for example, the pharmaceutical or cosmetic or agro-food industry.