The exhaust gas purification apparatus includes an additive injection valve for injecting an additive from an injection orifice thereof into an exhaust gas passage through which an exhaust gas flows, and a catalyst disposed downstream of the additive injection valve for promoting an exhaust purification reaction using the additive to purify the exhaust gas. The exhaust gas purification apparatus is configured to inject-supplies, from the additive injection valve, the additive to the exhaust gas by the additive injection valve at upstream of the catalyst, and supply the catalyst with the injected additive together with the exhaust gas utilizing an exhaust flow of the exhaust gas so that the exhaust purification reaction is performed on the catalyst. The additive injection valve is mounted such that the additive is injected from the injection orifice toward an exhaust upstream side with respect to a direction orthogonal to an exhaust gas flow direction.