A plasma display device is provided. The plasma display device includes a plasma display panel (PDP) which includes an upper substrate on which a plurality of black matrices are formed; and an external light shielding sheet which is disposed at a front of the PDP and includes a base unit and a plurality of pattern units that are formed on the base unit and that have a lower refractive index than the base unit. A distance between a pair of adjacent black matrices is 4-12 times greater than a distance between a pair of adjacent pattern units. Therefore, it is possible for a plasma display device to effectively realize black images and enhance bright room contrast with the aid of an external light shielding sheet which is disposed at a front of a PDP and which absorbs and shields as much external light incident upon the PDP as possible. Also, it is possible to reduce the probability of occurrence of the moire phenomenon and enhance the luminance of images displayed by a PDP by forming a plurality of pattern units on an external light shielding sheet so that the distance between the pair of adjacent pattern units can fall within a predetermined percentage range of the distance between the pair of adjacent black matrices formed on a PDP, or that the width of the pattern units can fall within a predetermined percentage range of the width of black matrices formed on the PDP.