A process for producing aluminum fluoride particles having a smooth surface, comprising the steps of adding aluminum fluoride seed crystals to a super-saturated solution of aluminium fluoride; allowing aluminum fluoride particles to be precipitated under heating and agitation; collecting the aluminium fluoride particles by filtration; and drying them, wherein: a super-saturated solution of aluminium fluoride containing 0.6 to 1.3 wt % of fluosilicic acid which is preferably obtained by reacting aluminum hydroxide with fluosilicic acid in an [Al(OH)3/H2SiF6] molar ratio of 1.80 to 1.90 is used as the crystallization mother liquor.
