A light modulating device is disclosed herein. The light modulating device is applied to a sunroof and/or glass of an automobile. In some embodiments, a light modulating device configured to be disposed in a sunroof of an automobile includes a light modulation film layer, wherein the light modulation film layer includes a first anisotropic substrate, a second anisotropic substrate, and a liquid crystal layer, wherein each of the first and second anisotropic substrates has a first surface, wherein the first surfaces of the first and second anisotropic substrates face each other; wherein the liquid crystal layer is disposed between the first surfaces of the first and second anisotropic substrates, and wherein a slow axis of the first or second anisotropic substrate is disposed parallel to a width direction of the automobile.