EXHAUST GAS PURIFICATION DEVICE AND ENGINE

An exhaust gas purification device for purifying exhaust gas of nitrogen oxides includes: a catalyst that is provided in an exhaust pipe (exhaust passage) for transporting exhaust gas, discharged from an engine, in a predetermined exhaust direction, and promotes the reduction of the exhaust gas; and an injection nozzle that is provided in the exhaust pipe so as to be upstream of the catalyst in the exhaust direction, and injects a reducing agent for reducing the exhaust gas. The injection nozzle includes an injection hole for injecting the reducing agent toward the catalyst, and a discharge hole for discharging a cooling medium in at least the direction opposite the exhaust direction.