The invention relates to a method for leaching the metals while granulating molten matte, comprising the steps of feeding a molten matte as a falling stream into a granulation chamber (30), spraying a liquid jet on the stream of molten matte to atomize the matte, and cooling the matte particles thus formed. The liquid jet comprises an acid solution containing water and sulfuric acid so that the acid solution starts leaching metals from the molten matte when the liquid jet contacts the molten matte. Part of product solution from granulation can be circulated to liquid jets to increase the metal content in the solution and to reduce its acid content.