An engine unit mounted to a vehicle frame, the engine unit includes: an engine; an engine support mechanism to be coupled to the vehicle frame, with at least one vibration absorbing mechanism disposed on each of both sides of the engine in an orthogonal direction to a crankshaft of the engine, to support the engine; an aftertreatment device to purify exhaust gas emitted from the engine; a base bracket provided to the engine support mechanism; and an upper bracket detachably fixed and mounted to the base bracket, the upper bracket supporting the aftertreatment device.