An apatite-containing film having photocatalytic activity is produced by a process comprising the steps of preparing a liquid mixture comprising a Ca-containing compound and a P-containing compound, subjecting the liquid mixture to reaction to prepare an apatite-precursor composition, applying the apatite-precursor composition to a substrate, and drying the applied apatite-precursor composition. The process may further comprise a heating step after the drying step. The apatite-precursor composition is preferably in the form of a sol.