The invention discloses an automatic adjusting type opening expanding device for woven bag production, and relates to the technical field of woven bag expanding tools. The automatic adjusting type opening expanding device comprises a base and a controller, a first electric lifting column is vertically and fixedly arranged at one end of one side of the top of the base, an expanding mechanism mounting frame is fixedly arranged at the top of the first electric lifting column, an expanding mechanism is fixedly arranged on the lower portion of the end, away from the first electric lifting column, of the expanding mechanism mounting frame, the controller is fixed to the top of the expanding mechanism mounting frame, the expanding mechanism is composed of a mounting column, mounting frames, lead screws, driving motors, positioning polished rods and expanding plates, the number of the mounting frames is four, and the mounting frames are distributed in a cross shape with the mounting column as the axis; and according to the expanding mechanism, the four expanding plates serve as expanding points, when the expanding mechanism is scaled, the four expanding points are distributed in a square shape all the time, and therefore the force applied to a woven bag by all the expanding points is equal, meanwhile, after the woven bag is expanded, an opening is in a square shape, and the area of the opening is guaranteed.