To provide an exhaust gas catalyst using a fired aluminum phosphate body with more excellent performance, and a method for producing it. (1) An exhaust gas purification catalyst including at least one platinum-group metal selected from the group consisting of Pt, Rh and Pd having a mean particle diameter of between 0.50 nm and 2.0 nm, supported on a tridymite-type fired aluminum phosphate body. (2) A method for producing an exhaust gas purification catalyst, including the steps of: firing aluminum phosphate obtained from an aqueous solution prepared to a pH of 3.5 to 4.5, at a temperature of between 1000° C. and 1200° C. for 2 hours or longer, to obtain a fired aluminum phosphate body, and supporting at least one type of platinum-group metal selected from the group consisting of Pt, Rh and Pd on the fired aluminum phosphate body.