NOVELTY - The fermenter for biological decomposition of organic material containing substrate and for the production of biogas obtained by the decomposition, comprises a longitudinally extending closed container (1) with an inlet (2) at forehead side of the container for the substrate and with an outlet (3, 4) at opposite end of the container for the treated substrate, and a discharge opening (15) for the biogas. The container shows a collecting tank with inclined walls arranged in the discharge area of the fermenter, and reaction volume cells that contain individually driven agitators (6).    USE - For biological decomposition of organic material containing substrate and for the production of biogas obtained by the decomposition.    ADVANTAGE - The fermenter is simple and economic.    DETAILED DESCRIPTION - The fermenter for biological decomposition of organic material containing substrate and for production of biogas obtained by the decomposition, comprises a longitudinally extending closed container (1) with an inlet (2) at forehead side of the container for the substrate and with an outlet (3, 4) at opposite end of the container for the treated substrate, and a discharge opening (15) for the biogas. The container shows a collecting tank with inclined walls arranged in the discharge area of the fermenter, and reaction volume cells that contain individually driven agitators (6) with circular moving agitating blades. The agitators are transverse to the longitudinal extension of an agitating shaft of the container for mixing of the substrate. The agitating shaft is arranged with axle bases that are smaller than the agitator diameter. The agitating blades cover an overlapping area in the rotating of the agitating shaft and show an agitating bar at their outside end. The agitating bar is divided, mutually staggered and arranged over the width of the container. A suction pipe is arranged in the discharge area of the fermentor for discharging of sediments. The collecting tank ends on their deepest point of the suction pipe. An INDEPENDENT CLAIM is included for a procedure for biological decomposition of organic material containing substrate and for extraction of the developing fermentation gas with the help of decomposition.    DESCRIPTION OF DRAWING(S) - The figure shows a fermenter:    Longitudinally extending closed container; (1)    Inlet; (2)    Outlet; (3, 4)    Agitator; (6)    Discharge opening. (15)