In one aspect of the invention, a thin layer capacitor element has a capacitor with a dielectric layer made of a metal oxide and a protective insulating layer made of a resin material, and a barrier layer made of a non-conductive inorganic material is provided between the capacitor and the protective insulating layer. In another aspect of the invention, a thin layer capacitor element is constituted so that a capacitor structure is covered with at least one protective insulating layer composed of a cured resin, the cured resin being formed from at least one resin precursor selected from the group consisting of thermosetting resins, photosetting resins and thermoplastic resins.