A mixed oxide is one of a group of potentially important catalysts in heterogeneous catalysis, because different catalytic behavior would be expected to emerge with a combination of their components. For the fundamental research on the catalytic properties of the mixed oxides, a perovskite-type oxide with a chemical formula of ABO, has been used as a suitable catalyst because of their well-defined and stable structure. For some perovskite-type oxides, their electronic structures have been pointed out to be similar to those of transition metals on the basis of theoretical calculations of valence band structures (1–4). Thus, one of the catalytic features of perovskite-type oxides is to be active for hydrogen-involving reactions such as the equilibration between hydrogen and deuterium, the hydrogenation and isomerization of olefins, and in particular the hydrogenolysis of hydrocarbons (5–11).