An optical component capable of changing polarization light state and a liquid crystal display (LCD) device using the same are provided. The optical component including a transparent substrate and a wavelength compensator is disposed at any position from the outer side of the LCD device to the outside in an output direction of an output light. The wavelength compensator is directly attached to the surface of the substrate to convert an output light of the LCD device from a linearly polarized light into a circularly polarized light or an elliptically polarized light, thereby effectively reducing eye fatigue. The LCD device is provided with such an optical component such that a linearly polarized light emerging from the LCD device is converted into a circularly polarized light or an elliptically polarized light to lessen the eye fatigue.