The invention discloses an automatic down filling machine, and belongs to the technical filed of a stowage unit for down and feather filled products. The automatic down filling machine comprises a box body, a first down stirring mechanism, a second down stirring mechanism, an electrical automatic control mechanism, a pair of weighing metering mechanisms, a pair of down output mechanisms, a pair of down filling heads and a box cavity channel start-and-stop mechanism. The box body comprises a box frame, a down storage box and a down delivering box. The first down stirring mechanism is used for stirring down in a down storage box cavity, and the second down stirring mechanism is used for stirring down in a down delivering box cavity. The pair of weighing metering mechanisms is connected with a pair of down leading out connector pipelines on two sides of the down delivering box, the pair of down output mechanisms is connected with the pair of weighing metering mechanisms, the pair of down filling heads is connected with the pair of down output mechanisms in a matched mode, and the box cavity channel start-and-stop mechanism is placed on the box frame. The electrical automatic control mechanism is provided with an electrical box body, a control panel, a programmable controller, a group of magnetic valves and a high-pressure air storage tank. The automatic down filling machine has the advantages of showing rhythmic continuity of down supplying, being capable of providing guarantee for subsequent continuously weighing and down filling, showing good down filling efficiency, reducing operation intensity of workers, eradicating down wasting and showing good automatic control effect.