A-site ordered perovskite-type oxide

Disclosed is a metal oxide material of which the volume is decreased in a practically effective temperature range. Specifically disclosed is a perovskite-type oxide represented by general formula (1). A'A 3 B 4 O 12 (1) (In the formula, A' and A are elements occupying the A-site in a perovskite-type oxide, wherein A' represents at least one metal element selected from a group consisting of La, Bi, Y, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Ca, Sr, Ba, Pb, Na and K, and A represents at least one transition metal element selected from a group consisting of Cu, Mn, Fe and Ni; and B is an element occupying the B-site in a perovskite-type oxide and represents at least one transition metal element selected from a group consisting of Fe, Ti, V, Cr, Cu, Mn, Co, Ni, Ge, Sn, Zr and Ru.)