Abstract: A dielectric ceramic for use in an electrostatic chuck, formed by firing in a reducing atmosphere a ceramic material mainly comprised of alumina, wherein said ceramic material comprises an alkaline earth metal in an amount of from 1.0 to 6.0% by weight in terms of oxide and a transition metal in an amount of from 0.5 to 6.0% by weight in terms of oxide, while controlling the dew point of atmosphere gas to be not more than 45.degree. C.Also disclosed is a method of making a dielectric ceramic for use in an electrostatic chuck, comprising firing a ceramic material mainly comprised of alumina and containing from 1.0 to 6.0% by weight of an alkaline earth metal in terms of oxide and from 0.5 to 6.0% by weight of a transition metal in terms of oxide, in a reducing atmosphere while controlling the dew point of atmosphere gas.