An exhaust gas purification catalyst disposed in an exhaust gas tube which is connected to an internal combustion engine, wherein the exhaust gas purification catalyst comprises a substrate and a catalyst coating layer formed on the substrate, wherein: the catalyst coating layer comprises catalyst particles, wherein said catalyst particles comprise a noble metal and a metal oxide, the catalyst coating layer having an upstream region extending by 40 to 60% of the entire length of the substrate from an upstream end of the catalyst in an exhaust gas flow direction and a downstream region corresponding to the remainder portion of the catalyst coating layer, the composition of the catalyst particle of the upstream region being different from that of the downstream region; in the downstream region of the catalyst coating layer, an average thickness of the coating layer is in a range from 25 μm to 160 μm, and a porosity measured by a weight-in-water method, as set out in the description, is in a range from 50 to 80% by volume, and in only the downstream region of the catalyst coating layer, high-aspect-ratio pores having an aspect ratio of 5 or more account for 0.5 to 50% by volume of the whole volume of voids, wherein the % by volume of the high-aspect ratio pores relative to the whole volume of voids is calculated as set out in the description, and the high-aspect-ratio pore has an equivalent circle diameter of from 2 μm to 50 μm in a cross-sectional image of a catalyst coating layer cross section perpendicular to an exhaust gas flow direction and has an average aspect ratio of from 10 to 50, wherein the average aspect ratio of the high-aspect ratio pore is measured by analyzing a cross-sectional image of a catalyst coating layer cross section perpendicular to an exhaust gas flow direction of the substrate as set out in the description; wherein the equivalent circle diameter is measured as set out in the description. the catalyst coating layer comprises catalyst particles, wherein said catalyst particles comprise a noble metal and a metal oxide, the catalyst coating layer having an upstream region extending by 40 to 60% of the entire length of the substrate from an upstream end of the catalyst in an exhaust gas flow direction and a downstream region corresponding to the remainder portion of the catalyst coating layer, the composition of the catalyst particle of the upstream region being different from that of the downstream region; in the downstream region of the catalyst coating layer, an average thickness of the coating layer is in a range from 25 μm to 160 μm, and a porosity measured by a weight-in-water method, as set out in the description, is in a range from 50 to 80% by volume, and in only the downstream region of the catalyst coating layer, high-aspect-ratio pores having an aspect ratio of 5 or more account for 0.5 to 50% by volume of the whole volume of voids, wherein the % by volume of the high-aspect ratio pores relative to the whole volume of voids is calculated as set out in the description, and an average thickness of the coating layer is in a range from 25 μm to 160 μm, and a porosity measured by a weight-in-water method, as set out in the description, is in a range from 50 to 80% by volume, and in only the downstream region of the catalyst coating layer, high-aspect-ratio pores having an aspect ratio of 5 or more account for 0.5 to 50% by volume of the whole volume of voids, wherein the % by volume of the high-aspect ratio pores relative to the whole volume of voids is calculated as set out in the description, and the high-aspect-ratio pore has an equivalent circle diameter of from 2 μm to 50 μm in a cross-sectional image of a catalyst coating layer cross section perpendicular to an exhaust gas flow direction and has an average aspect ratio of from 10 to 50, wherein the average aspect ratio of the high-aspect ratio pore is measured by analyzing a cross-sectional image of a catalyst coating layer cross section perpendicular to an exhaust gas flow direction of the substrate as set out in the description; wherein the equivalent circle diameter is measured as set out in the description.