The present invention relates to a catalytic converter apparatus for purifying exhaust gas from an internal combustion engine for vehicles. The catalytic converter apparatus includes a first catalytic converter that holds a first catalyst and that is to be coupled to a side of the engine, and a second catalytic converter that holds a second catalyst and that is coupled to a rear of the first catalytic converter. Each of the first and second catalysts has a catalytic support on which a wash coat layer having a thickness equal to or less than 0.2 mm is formed. The wash coat layer includes a first wash coat layer and a second wash coat layer, and each of the first and second wash coat layers has voids therein. This catalytic converter apparatus achieves an improved purification property with a small number of cells and a small amount of noble metal.