A (Li, Na, K)(Nb, Ta)O3-based piezoelectric/electrostrictive ceramic composition having large electric field-induced distortion at the time of application of a high electric field is provided. A perovskite oxide is synthesized which contains Li (lithium), Na (sodium) and K (potassium) as A-site elements and contains at least Nb (niobium) and Sb (antimony) out of Nb, Ta (tantalum) and Sb as B-site elements, the ratio of the total number of atoms of the A-site elements to the total number of atoms of the B-site elements being larger than 1, and then a Bi (bismuth) compound is added and reacted. The amount of addition of the Bi compound with respect to 100 molar parts of the perovskite oxide is preferably not less than 0.02 molar part nor more than 0.1 molar part in terms of Bi atoms.