A liquid film dust arrester is installed to face a gas flow containing dust and flowing out from a gas discharge pipe. The arrester includes a gas flow blocking unit arranged vis-à-vis the gas flow, a liquid dispersion unit having a dispersion section arranged at a position near the center of the gas flow blocking unit and upstream relative to the gas flow blocking unit as viewed in the flowing direction of the gas flow so as to face the gas flow blocking unit, a liquid ejection unit having an ejection port disposed vis-à-vis the dispersion section and configured to eject liquid from the ejection port, and a liquid film forming unit. The dispersion section comprises a smooth surface that causes the ejected liquid to flow and disperse on the smooth surface, and the liquid film is formed to face the gas flow flowing through the flow path.