CIRCUIT BOARD USING A SINTERED OXIDE COMPACT

Provided is an electric conductor which is formed from a sintered oxide compact that has high electric conductivity and a small B-value (temperature coefficient). The sintered oxide compact is represented by a composition formula : REaCobNicOx (where RE represents a rare earth element, a + b + c = 1, and 1.3 ‰¤ x ‰¤ 1.7); the sintered oxide compact comprises a perovskite phase with a perovskite-type oxide crystal structure; a, b, and c satisfy the following relationships : 0.474 ‰¤ a ‰¤ 0.524 , 0.2000 ‰¤ b ‰¤ 0.375 , and 0.125 ‰¤ c ‰¤ 0.300 ; and the sintered oxide compact further comprises RE 4 Co 3 O 10 or RE 4 Ni 3 O 10 in addition to the perovskite phase.