PROBLEM TO BE SOLVED: To provide a coating material having a phosphate film stable and preferably excellent in tissue affinity, or a coating material having an apatite film on a base material with high corrosion resistance.SOLUTION: A method for producing the phosphate film material includes a hydrothermal treatment process for heating for reaction (A) the base material and (B) an acid aqueous solution containing phosphate and having pH less than 5, to a temperature higher than 100°C under pressure higher than one barometric pressure, the base material being selected from a group consisting of ceramics, a polymer compound, a carbon material, metal whose passive state destructive potential measured with an acid aqueous solution ISO 10271 containing phosphate and having pH less than 5 is not less than the passive state destructive potential of 304 stainless steel measured in the same conditions, and a composite material of these or an apatite coating material includes a base material selected from a group consisting of ceramics, a polymer compound, a carbon material, metal and a composite material of these, a phosphate film provided on the base material and containing phosphate other than apatite, and the apatite film provided on the phosphate film.
