A polarizer of a liquid crystal display device and a method for manufacturing a liquid crystal display device using the same is disclosed. The polarizer includes a main body, a protection film on the main body, and a cutting line formed on the protection film. A method for manufacturing a liquid crystal display device includes providing a liquid crystal panel and a protection film having an active region and a dummy region, the protection film including at least a cutting line in the dummy region or a boundary area between the active region and the dummy region; attaching the protection film to a polarizer; attaching the polarizer to a liquid crystal panel; and, removing the dummy region of the protection film along the cutting line from the liquid crystal panel.