A double-sided polarizer includes a polarizing film, a first adhesive layer formed on one surface of the polarizing film, a second adhesive layer formed on the other surface of the polarizing film, a first transparent film formed on the first adhesive layer, and a second transparent film formed on the second adhesive layer, wherein the first adhesive layer and the second adhesive layer are formed of an active energy line-curable adhesive and the first adhesive layer is 0.1 μm to 3 μm thick, and there is also provided an optical device including the double-sided polarizer.