The disclosure relates to a light valve device and smart glass. The light valve device includes a transparent substrate, a rollable light shielding film, and a limit fixing structure. The light shielding film includes an upper surface, a lower surface, and a plurality of end surfaces between the upper surface and the lower surface, the end surface including at least a first end surface and a second end surface that are opposite to each other, an edge portion of the light shielding film proximate to the first end surface being fixed on the transparent substrate, and the light shielding film being capable of being rolled to move the second end surface toward the first end surface. The limit fixing structure includes a first fixing member arranged on a portion of the light shielding film proximate to the second end surface; and a second fixing member arranged on the transparent substrate and configured to cooperate with the first fixing member to fix the light shielding film after the light shielding film is unrolled.