Patent ID: 7282670

Claim:
A ceramic heater, comprising an insulative ceramic base material and a heat-generating resistor embedded in the insulative ceramic base material, being characterized in that the heat-generating resistor comprises, as main components, silicon nitride, an electrically conductive compound and a grain boundary amorphous glass phase; the amount of a rare earth element contained in the heat-generating resistor is less than 2% mol in terms of its oxide (RE 2 O 3 ; RE representing a rare earth element); and, when the mol number of the rare earth element in terms of its oxide is represented by A and the mol number of an amount of excess oxygen in terms of silicon dioxide (SiO 2 ) contained in the heat-generating resistor is represented by B, a ratio R computed by the following formula (1) is 0.3 or less: R=A /( A+B ) (1).