In order to provide a film-forming powder using hydroxyapatite which is a main component of teeth, or hydroxyapatite in which a color tone adjuster is blended, the powder being used in a jet-device for forming a film on a surface of a tooth by spraying the powder on the tooth, and being suitable for forming a film having a high hardness and extremely low solubility in acid in a short period of time, and suitable for forming a film of a powder conforming to the color tone of a tooth in a short period of time； a hydroxyapatite powder calcined in an inert gas atmosphere at 600 to 1350° C., a powder obtained by applying to the hydroxyapatite powder calcined at 600 to 1350° C. plasma irradiation, or plasma irradiation and mechanical energy, and additionally a film-forming powders obtained by blending color tone adjusters into these hydroxyapatite powders are produced.
