| abstract |
A ceramic heater of the invention includes a ceramic structure; a heat-generating resistor embedded in the ceramic structure; and a feeder line embedded in the ceramic structure so as to be connected, at one end thereof, to the heat-generating resistor. The feeder line is made of metal, and metal grains of a center region of the feeder line are greater in grain size than metal grains of an outer periphery region of the feeder line. Even if a crack developed in the outer periphery region of the feeder line propagates through grain boundaries in the outer periphery region and comes near the center region, propagation of the crack through the interior of the center region can be suppressed. |