Abstract: A frameless auto-dimming rear view mirror, including an absorptive-type polarizing layer, a liquid crystal dimming layer and a reflective-type polarizing. The liquid crystal dimming layer includes a first transparent substrate, a first transparent electrode, a first alignment layer, a liquid crystal layer, a second alignment layer, a second transparent electrode and a second transparent substrate arranged in sequence. The first transparent substrate is adjacent to the absorptive-type polarizing layer, and its position corresponds to the position of the second transparent substrate, and the first transparent substrate is provided with a step which is beyond the position of the second transparent substrate at its edge.