A method for producing an exhaust gas purification catalyst comprising: a substrate ; a catalyst coating layer that is formed of a porous support and is formed on a surface of the substrate ; and a noble metal catalyst that is supported on the porous support of the catalyst coating layer , wherein: the catalyst coating layer is formed as a layer structure having an upper layer relatively farther from the substrate surface and a lower layer relatively closer to the substrate surface; Rh particles are supported as the noble metal catalyst in the upper layer ; Pd particles are supported as the noble metal catalyst in the lower layer ; the porous support of the lower layer that supports the Pd particles is formed by an ACZ composite oxide made of alumina (Al 2 O 3 ), ceria (CeO 2 ), and zirconia (ZrO 2 ); characterized in that the ACZ composite oxide is produced by an alkoxide method; wherein starting materials in the alkoxide method are a metal alkoxide and a metal salt that is used for components other than the metal alkoxide; Al, Ce, and Zr are all converted into the metal alkoxide, or at least one of Al, Ce, and Zr is converted into the metal alkoxide; the starting materials are dissolved in a suitable solvent and mixed and hydrolysis and polycondensation reactions are carried out, after which the ACZ composite oxide is obtained by a heat treatment that is performed at temperature from at least 500°C to not more than 900°C; the porous support of the upper layer that supports the Rh particles is formed by a mixture of alumina and a CZ composite oxide made of ceria and zirconia; and a Ce/Zr atomic ratio in the CZ composite oxide is from at least 0.7 to not more than 0.8. a substrate ; a catalyst coating layer that is formed of a porous support and is formed on a surface of the substrate ; and a noble metal catalyst that is supported on the porous support of the catalyst coating layer , the catalyst coating layer is formed as a layer structure having an upper layer relatively farther from the substrate surface and a lower layer relatively closer to the substrate surface; Rh particles are supported as the noble metal catalyst in the upper layer ; Pd particles are supported as the noble metal catalyst in the lower layer ; the porous support of the lower layer that supports the Pd particles is formed by an ACZ composite oxide made of alumina (Al 2 O 3 ), ceria (CeO 2 ), and zirconia (ZrO 2 ); characterized in that the ACZ composite oxide is produced by an alkoxide method; wherein starting materials in the alkoxide method are a metal alkoxide and a metal salt that is used for components other than the metal alkoxide; Al, Ce, and Zr are all converted into the metal alkoxide, or at least one of Al, Ce, and Zr is converted into the metal alkoxide; the starting materials are dissolved in a suitable solvent and mixed and hydrolysis and polycondensation reactions are carried out, after which the ACZ composite oxide is obtained by a heat treatment that is performed at temperature from at least 500°C to not more than 900°C; the porous support of the upper layer that supports the Rh particles is formed by a mixture of alumina and a CZ composite oxide made of ceria and zirconia; and a Ce/Zr atomic ratio in the CZ composite oxide is from at least 0.7 to not more than 0.8. <EOS>