Abstract: In a device for supplying ammonia (NH3) to a reduction catalytic converter arranged in an exhaust system of an internal combustion engine comprising a container for storing a precursor body capable of generating ammonia when heated by a heating device disposed in the container for the thermolytic decomposition of the precursor material, the heating device includes a heating surface arranged adjacent the precursor body and means are provided for biasing the precursor material body in firm contact with the heating device surface for direct heat transfer to the precursor body, and the heating device is connected to a control unit for controlling the energization of the heating device depending on the NH3 requirements of the reduction catalytic convertor.