The invention discloses an automatic paint spraying device. The automatic paint spraying device comprises a paint spraying base body, wherein a paint stirring box is fixedly arranged on the top of theright side of the paint spraying base body; a paint stirring cavity is formed in the paint stirring box, a paint adding pipe is arranged at the top of the paint stirring box, and a paint adding cavity communicating with the paint stirring cavity is formed in the paint adding pipe; a first hole cavity is formed in the part, right at the lower side of the paint stirring cavity, of the paint spraying base body, and a first rotating arm which is arranged in an up-down extending mode is rotationally connected between the first hole cavity and the paint stirring cavity in a coordinated mode; the extending end of the top of the first rotating arm penetrates into the paint stirring cavity, and the tail end of the first rotating arm is in power connection with a paint stirring device, and the expanding end of the bottom of the first rotating arm penetrates into the first hole cavity, and a first bevel wheel is fixedly arranged at the tail end of the first rotating arm; an upward-extending second hole cavity is formed in the part, on the left side of the first hole cavity, of the paint spraying base body, and a third hole cavity is arranged in the part, on the right side of the first hole cavity, of the paint spraying base body, wherein the third hole cavity is arranged in a front-back extending mode.