Abstract: Disclosed is a device for preparing a cosmetic product, in the form of a cream, an emulsion, a lotion, a gel, a suspension, a mask or a gommage, in a first container from a base and at least one excipient. The device includes: the first container intended to contain the prepared cosmetic product, including: a free end that is open at the top and equipped with a connector, and a free end that is open at the bottom and equipped with a connector, a cartridge equipped with a connection to the free end, containing the base, an agitator, with a connection to the free end, open at the top, and at least one supply unit collaborating with at least one reservoir.