To obtain a ceramic sintered material not generating a crack, having high insulating resistance and a high thermal expansion coefficient, and excellent in durability by blending a mother material consisting of a nitride-based ceramic material with a prescribed amount of one or more kinds of a carbide, a silicate, a nitride, a boride of a metal having a larger thermal expansion coefficient than the motor material.

This ceramic sintered material is obtained by blending a sintered material consisting of Si3N4, a sialon and AlN as a main component as a mother material with WC, MoSi2, TiN, TiB2, etc., as a metal carbide, etc., of which blending amount is ≥1vol.% and <5vol.%. A volume receptivity of the obtained sintered material is ≥108τ.cm and an insulation breaking strength thereof is ≥1kV/mn. The figure shows a side view of a ceramic sintered material applied for an insulating part of a ceramic heating body before finishing the same by grinding. The ceramic sintered material 1 consists of a silicone nitride-based sintered material for an insulating part of a ceramic heater 6 equipped with a heat generating resistor 2, a lead part 3, a lead wire 4 and an electrode drawing out port 5.