A combustion chamber assembly unit, especially for a vaporizing burner and particularly especially for a vehicle heater, includes at least two combustion chamber elements (12, 20, 26, 32, 50, 52, 64, 102, 126) with wall areas (12, 34, 46, 54, 64, 104, 130, 140, 142). The at least two combustion chamber elements are arranged in a radially staggered pattern in relation to a longitudinal axis (L) of the combustion chamber and are fixed to one another by laser welding.