Provided is a polarizing plate with a phase difference layer having excellent high-temperature durability. A polarizing plate with a phase difference layer according to one embodiment of the present invention comprises a phase difference layer and a polarizing plate including a polarizer, wherein an angle formed between the absorption axis of the polarizer and the slow axis of the phase difference layer is 40-50°. The ratio x/y between a contraction dimension x in the slow axis direction of the phase difference layer after being left under a heating condition of 80°C for 500 hours for an evaluative square shape defined in the center of the polarizing plate with the phase difference layer, and the contraction dimension y in the fast axis direction of the phase difference layer for the same evaluative square shape, is 0.994 to 1.004.