Exhaust gas purification device

An exhaust gas purification device comprising:

• a substrate with a total length (Ls), the substrate having an upstream end through which an exhaust gas flows into the substrate and a downstream end through which the exhaust gas flows out from the substrate;
• a first catalyst layer disposed on the substrate in a first region, the first region extending between the downstream end and a first position, the first position being at a first distance (La) from the downstream end toward the upstream end, the first catalyst layer containing rhodium, the first distance (La) being from 50% to 70% of the total length (Ls) of the substrate;
• a second catalyst layer disposed on the substrate in a second region, the second region extending between the upstream end and a second position, the second position being at a second distance (Lb) from the upstream end toward the downstream end, the second catalyst layer containing rhodium and an oxygen storage material, the second distance (Lb) being 50% or more of the total length (Ls) of the substrate, the oxygen storage material containing a pyrochlore type Ce—Zr composite oxide and a fluorite type Ce—Zr composite oxide at a weight ratio of from 0.2:1 to 0.4:1;
• and
• a third catalyst layer disposed on the second catalyst layer in a third region, the third region extending between the upstream end and a third position, the third position being at a third distance (Lc) from the upstream end toward the downstream end, the third catalyst layer containing palladium, the third distance (Lc) being 40% or less of the total length (Ls) of the substrate.