The utility model discloses a sealing dustproof device for a miniature ball bearing. The sealing dustproof device comprises an outer wheel, an inner wheel, a fixing cover and a sealing ring. The sealing dustproof device is characterized in that a dustproof groove on the outer wheel adopts a trapezoid notch, and the fixing cover adopts a Z shape. The fixing cover can be conveniently pressed into the dustproof groove of the bearing through a simple manual pressure machine, thus a circlip is not required, which ensures the chance decrease of bearing touch, therefore, the possibility of the dust falling into the bearing is reduced, and the bearing quality is improved to a large extent; because of eliminating one part bearing, the production efficiency is remarkably improved; the fixing cover is made into a whole, and is molded through a stamping die in one step, and the costs of the material and the die are low; in the structure, the processing of the workblank dustproof groove is easy, therefore, the workblank dustproof grooves can be mass produced by the existing workblank manufacturers.