Method of producing perovskite complex oxide and precursor substance used in the method

A method of producing a perovskite complex oxide is provided wherein, at the time of producing a perovskite (RTO3) complex oxide phase by heat treating a precursor substance that is a powdery starting material containing at least one rare earth element R and at least one transition metal element T, there is used as the precursor substance an amorphous substance containing the R and T components at the content ratio required for producing the complex oxide. The obtained perovskite complex oxide has a specific surface area exceeding 10 m2/g.