A high-brightness polarizing plate of the present invention comprises a polarizing plate that comprises a polarizer and a protective film prepared on one or both sides of the polarizer, a brightness enhancement film and an adhesive layer through which the polarizing plate and the brightness enhancement film are laminated with the protective film interposed between them, wherein the protective film has an in-plane retardation Re of 0 to 10 nm and a thickness-direction retardation Rth of -30 to 10 nm, wherein Re=(nx-ny)d and Rth={(nx+ny)/(2-nz)}d. The high-brightness polarizing plate has a small color shift, and can be applied to various image displays such as liquid crystal displays.