Abstract: A device for decomposing ammonia into a nitrogen-hydrogen mixture. The device comprising a cylindrical combustion chamber, a device for supplying air-ammonia mixture, at least one main channel for its supply, a tangential swirler, a spark plug installed in the combustion chamber, and a channel for supplying auxiliary fuel with increased flammability. A cylindrical body is introduced, inside of which a cylindrical combustion chamber is located coaxially with the formation between them, the entrance of the main channel and the tangential swirler, an additional annular channel for supplying and heating the air-ammonia mixture, wherein the cylindrical side surfaces of the body and the combustion chamber have at least one through hole for installation of the spark plug, a flame sensor, a device for secondary air supply and a flame stabilizer are introduced, wherein the combustion chamber is a cooling chamber, at the outlet of which a catalytic unit is installed.