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 (Δ ε>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 , 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 positive biaxial retardation film (11; 13) defined by a following Equation is aligned between the liquid crystal cell and the second polarizer plate , an optical axis (12; 14) of the positive biaxial retardation film (11; 13) is perpendicular to the absorption axis of the second polarizer plate 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, characterized in that an in-plane retardation value of the positive biaxial retardation film (11; 13) is equal to or less than 180nm at a wavelength of 550nm and that the positive biaxial retardation film (11; 13) has a normal wavelength dispersion or flat wavelength dispersion characteristic, and that the first polarizer plate and the second polarizer plate have internal protective films respectively. 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 (Δ ε>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 , 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 positive biaxial retardation film (11; 13) defined by a following Equation is aligned between the liquid crystal cell and the second polarizer plate , an optical axis (12; 14) of the positive biaxial retardation film (11; 13) is perpendicular to the absorption axis of the second polarizer plate 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, characterized in that an in-plane retardation value of the positive biaxial retardation film (11; 13) is equal to or less than 180nm at a wavelength of 550nm and that the positive biaxial retardation film (11; 13) has a normal wavelength dispersion or flat wavelength dispersion characteristic, and that the first polarizer plate and the second polarizer plate have internal protective films respectively. <EOS>