A three-way catalyst for purifying exhaust including noble metal components, enables sintering of the noble metal to be suppressed even at high temperature, enables carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx) to be removed and a method for purifying exhaust gas. A carrier having a honeycomb structure is coated with two or more layers of the catalyst compositions, an upper layer including a heat resistant inorganic oxide supporting Pd and a La-containing oxide, a lower layer including a heat resistant inorganic oxide supporting Rh. The content of La in terms of La2O3 is 9.6 g/L to 23 g/L, the content of Ce in terms of CeO2 is 5 g/L to 20 g/L, and the content of Ba in terms of BaO is 1.2 g/L or less per unit volume of the honeycomb structure.