A liquid crystal display device of at least one embodiment of the present invention includes a TN-mode liquid crystal display panel which is constituted by pixels of three colors (red, green, and blue) and a color filter. A thickness of a liquid crystal layer (cell thickness) is determined on a basis of a retardation value of green light or red light, which has a larger wavelength than blue having shortest wavelength among the three colors. A display data switching circuit carries out gradation conversion of shifting input gradation values to lower gradation values with respect to image data supplied to pixels of blue. Thus, grayscale inversion is prevented. The liquid crystal display device of the present invention produces an effect of improving transmittance of pixels of colors having wavelengths other than the wavelength of blue.