The aim of the invention is to provide a method for gasifying organic materials which is simple to carry out and requires minimal equipment and which produced an undiluted gas of high calorific value. The inventive method should eliminate the need to use fluid beds and heat exchangers with high temperatures on both sides, with the heat being transferred from the furnace to a heat-carrying medium in a particularly defined way. To this end, the feed material is divided into a volatile phase and a solid carbon-containing residue in the pyrolysis reactor by circulating a hot heat-carrying medium. After the reaction agent has been added, said volatile phase is converted into the product gas by further heating in the reaction area, also using the heat-carrying medium. The solid, carbon-containing residue is separated from the heat-carrying medium in the separating stage and burnt in the furnace. The heat-carrying medium is heated by the waste gases of the furnace in the heating area and then returned to the reformer and then the pyrolysis reactor.