A method of producing a fluoroapatite is provided. The method comprises preparing a slurry containing a hydroxyapatite which has at least one hydroxyl group, preparing a hydrogen fluoride-containing solution containing a hydrogen fluoride, mixing the hydrogen fluoride-containing solution with the slurry to obtain a mixture to thereby adjust a pH of the mixture in the range of 2.5 to 5, and reacting the hydroxyapatite with the hydrogen fluoride in the mixture in a state that the pH of the mixture is adjusted within the above range to thereby obtain the fluoroapatite by substituting the at least one hydroxyl group of the hydroxyapatite with fluorine atom of the hydrogen fluoride. The method can produce the fluoroapatite having improved acid resistance by reducing an impurity, such as ammonia, derived from a raw material to a low or very low level. Further, a fluoroapatite having high acid resistance is also provided. Furthermore, an adsorption apparatus using such a fluoroapatite is provided.