An exhaust post-treatment device is designed in a layered fashion and comprises an exhaust cleaning arrangement lying between a supply chamber and a transition chamber with soot filters lying at both sides of a denitrification-catalytic converter unit, with the transition chamber comprising a mixing chamber open towards the denitrification-catalytic converter unit, in which starting at the soot filters via separate guide channels, the exhaust is injected in the opposite direction of flow and which mixing chamber is limited by guide panels, which form walls of the guide channels extending encompassing along the housing towards the mixing chamber.