PURPOSE: To contrive improvement in voltage output coefficient and mechanical strength, by specifying average pore diameter and porosity.

CONSTITUTION: This calcined compact is a porous calcined compact, consisting essentially of PbZrO3-PbTiO3 based ceramics and having ≤1000A average pore diameter and ≥50% porosity. This calcined compact has a sufficient mechanical strength in spite of a high porosity and voltage output coefficient. If the porosity in the calcined compact is <50%, it is difficult to increase the voltage output coefficient to ≥0.1Vm/N. If the average porosity exceeds 1000 A, mechanical strength is deteriorated when the porosity is increased to ≥50%, resulting in difficult machining. The above-mentioned calcined compact can be produced by hydrolyzing and condensing a lead alkoxide, Zr alkoxide and Ti alkoxide in an aqueous solvent and calcining the resultant reaction product in the form of a sol or gel.