There is disclosed a metal particle-dispersed composite oxide comprising a matrix material containing a composite oxide comprising a non-reducible metal oxide and an easily reducible metal oxide, the composite oxide containing 0.01 to 0.25 mol % of at least one additive metal selected from Al, Sc, Cr, B, Fe, Ga, In, Lu, Nb and Si, surface metal particles precipitated on an outer surface of the matrix material containing the composite oxide, and inner metal particles precipitated on an inner surface of the matrix material containing the composite oxide.