CERAMIC HEATER

PROBLEM TO BE SOLVED: To improve airtightness of a junction part and secure it for a long period of time by airtightly joining a coating plate of ceramic sintered product for covering the whole area of a junction surface of a substrate and the substrate of ceramic sintered product with an adhesive and forming an oxynitride glass layer containing specific elements on an junction interface. SOLUTION: A substrate 2 of a ceramic sintered product provided with a recessed groove on its surface and a coating lower plate 3a of ceramic sintered product sandwich and support a heater element 8 in a recessed groove. Junction parts 7, 10 for airtightly joining between the substrate 2 and the coating lower plate 3a and between the coating lower plate 3a and an upper plate 3b for sandwiching and supporting the electrode plate 4 and the substrate 2 and the coating lower plate 3a are formed as an oxynitride glass layer, containing two kinds of elements selected from group IIIa of the periodic table, aluminum, and silicon so as to improve airtightness of the junction parts 7, 10 and secure airtightness over a long period of time. Thus, the glass layer of this composition has good wettability with the ceramic sintered product and has superior junction strength, satisfactory airtightness of the junction parts 7, 10, small dispersion in the junction strength, and superior heat resistance.