Engine exhaust gas purification apparatus

An oxidation catalyst 12 is disposed in an exhaust passage 11 positioned upstream of a DPF 13. When the temperatures of the oxidation catalyst 12 and the DPF 13 are low, a post-injection timing is advanced and a post-injection fuel is combusted in a cylinder, thereby preventing the post-injection fuel from flowing into and being deposited in the DPF 13 and, also, implementing quick rise of the temperatures of the oxidation catalyst 12 and the DPF 13 by raising an exhaust gas temperature. After the temperature of the oxidation catalyst 12 has reached a high level, the post-injection timing is retarded. Then, the post-injection fuel is fed to the oxidation catalyst 12 and catalytic reaction heat generated therein is utilized to implement raise of the temperature of the DPF 13.