Scandium fluoride (ScF3) microtubes with nanoscale wall thickness were for the first time successfully synthesized by an interface-assisted technique at the surface of a scandium nitrate aqueous solution without the addition of any surfactant as a result of interaction with hydrofluoric acid from the gaseous phase in only 30 min. X-ray diffraction analysis, scanning electron microscopy, helium ionic microscopy, transmission electron microscopy (TEM), and high-resolution TEM (HRTEM) were used to examine the morphology and crystal structure of ScF3 microtubes. The results show that the ScF3 microtube is single-crystalline and has a hexagonal structure. A hypothetical model of thin-walled microtube formation is proposed.