EXHAUST GAS PURIFICATION DEVICE AND ENGINE

[Problem] To provide: an exhaust gas purification device for restraining thermal damage to an injection nozzle without being bound by an air assist function of reducing agent injection; and an engine including the exhaust gas purification device. [0002] [Solution] An exhaust gas purification device 1 for purifying exhaust gas of nitrogen oxides includes: a catalyst 14 that is provided in an exhaust pipe 4 (exhaust passage) for transporting exhaust gas, discharged from an engine 2, in a predetermined exhaust direction, and promotes the reduction of the exhaust gas; and an injection nozzle 11 that is provided in the exhaust pipe 4 so as to be upstream of the catalyst 14 in the exhaust direction, and injects a reducing agent for reducing the exhaust gas. The injection nozzle 11 includes an injection hole 16 for injecting the reducing agent toward the catalyst 14, and a discharge hole 18 for discharging a cooling medium in at least the direction opposite the exhaust direction.