A semiconductor ceramic composed of barium titanate, lead titanate, strontium titanate, and calcium titanate as primary components, includes samarium oxide as a semiconductor-forming agent in the primary components, and the average diameter of crystalline particles of the semiconductor ceramic is about 7 to 12 &mgr;m. The semiconductor ceramic has a resistivity at room temperature not greater than 3.5 &OHgr;cm, a withstand voltage not less than 50 V/mm, a resistance-temperature coefficient &agr;10-100 not less than 9%/°C. and also has less variability of resistance.