In the production of hydrofluoric acid by holding fluorine by adsorption from a drainage water or waste water containing fluorine with an inorganic ceramic adsorbent mainly composed of active alumina and silicon dioxide and producing hydrofluoric acid from the adsorbent provided after the adsorption, the object is to increase the efficiency of production of hydrofluoric acid and prevent the degradation of the adsorbent. A hydrofluoric acid production apparatus for producing hydrofluoric acid by holding a fluorine ion by adsorption from a fluorine compound or fluorine mixture which contains a fluorine ion with a ceramic adsorbent mainly composed of active alumina and silicon dioxide and producing hydrofluoric acid from the adsorbent provided after the adsorption, the apparatus comprising adistillation means for reacting the adsorbent with a strong alkali or strong acid and generating hexafluorosilicic acid gas by addition of crystalline silicon dioxide, and a cooling means for coolingand hydrolyzing the hexafluorosilicic acid gas produced in the distillation means to produce hydrofluoric acid.