To improve the heat resistance of an exhaust treatment device 4 for an exhaust system 1 for an internal combustion engine, particularly, an internal combustion engine mounted on a motive power vehicle.

The device 4 comprises a housing 10 in which at least one exhaust treatment inserted component 11 is arranged. The housing 10 consists of at least two housing parts 13, 14, at least one being formed of a ferrite material and the other being formed of an austenite material. To improve the heat resistance of the device 4, at least one ferrite housing part 13 is fixed to at least one austenite housing part 14 via a joint portion 5. The joint portion 5 is formed of a material having a thermal expansion coefficient within the thermal expansion coefficient of the ferrite material to the thermal expansion coefficient of the austenite material.