An in-plane switching liquid crystal display comprising: a first polarizer plate; a second polarizer plate; and a liquid crystal cell, which is horizontally aligned and filled with liquid crystal of positive dielectric anisotropy (Δε>0) or negative dielectric anisotropy (Δε<0), an optical axis of the liquid crystal filled in the liquid crystal cell being aligned in-plane in parallel to the first and second polarizer plates (1, 2), wherein an absorption axis of the first polarizer plate is perpendicular to an absorption axis of the second polarizer plate, the optical axis of the liquid crystal filled in the liquid crystal cell is parallel to the absorption axis of the first polarizer plate, a first positive biaxial retardation film defined by a following Equation is aligned between the liquid crystal cell and the first polarizer plate, a second positive biaxial retardation film defined by the following Equation is aligned between the liquid crystal cell and the second polarizer plate, characterized in that an optical axis of the first positive biaxial retardation film is parallel to the absorption axis of the first polarizer plate, an optical axis of the second positive biaxial retardation film is parallel to the absorption axis of the second polarizer plate, an in-plane retardation value of the first positive biaxial retardation film is equal to or less than 150 nm at a wavelength of 550 nm, and an in-plane retardation value of the second positive biaxial retardation film is in a range of 200 nm to 350 nm at a wavelength of 550 nm. Equation n x ≠n y ≠n z and n x > n y and n z > n y, wherein n x and n y are in-plane refractive indexes, n z is a thickness refractive index, and the positive biaxial retardation film (11, 13) has a positive in-plane retardation value (R in = d × (n x - n y)) and a positive thickness retardation value (R th = d × (n z - n y)) in which d is a thickness of a film, wherein both positive biaxial retardation films (11, 13) are used as protective films for the polarizer plates (1, 2). a first polarizer plate; a second polarizer plate; and a liquid crystal cell, which is horizontally aligned and filled with liquid crystal of positive dielectric anisotropy (Δε>0) or negative dielectric anisotropy (Δε<0), an optical axis of the liquid crystal filled in the liquid crystal cell being aligned in-plane in parallel to the first and second polarizer plates (1, 2), wherein an absorption axis of the first polarizer plate is perpendicular to an absorption axis of the second polarizer plate, the optical axis of the liquid crystal filled in the liquid crystal cell is parallel to the absorption axis of the first polarizer plate, a first positive biaxial retardation film defined by a following Equation is aligned between the liquid crystal cell and the first polarizer plate, a second positive biaxial retardation film defined by the following Equation is aligned between the liquid crystal cell and the second polarizer plate, characterized in that an optical axis of the first positive biaxial retardation film is parallel to the absorption axis of the first polarizer plate, an optical axis of the second positive biaxial retardation film is parallel to the absorption axis of the second polarizer plate, an in-plane retardation value of the first positive biaxial retardation film is equal to or less than 150 nm at a wavelength of 550 nm, and an in-plane retardation value of the second positive biaxial retardation film is in a range of 200 nm to 350 nm at a wavelength of 550 nm. Equation n x ≠n y ≠n z and n x > n y and n z > n y, wherein n x and n y are in-plane refractive indexes, n z is a thickness refractive index, and the positive biaxial retardation film (11, 13) has a positive in-plane retardation value (R in = d × (n x - n y)) and a positive thickness retardation value (R th = d × (n z - n y)) in which d is a thickness of a film, wherein both positive biaxial retardation films (11, 13) are used as protective films for the polarizer plates (1, 2).