NOVELTY - The anaerobic digester comprises a space portion located in a receiving tank for receiving a mixture containing an organic mixture and anaerobes, a stirrer stirring the mixture in the receiving tank, an inlet introducing the mixture into the receiving tank, an outlet discharging the effluents from the receiving tank, a filtration unit located within the receiving tank for filtering the mixture in the tank, a conveying path formed along the fluid portion between the inlet and the outlet, a spray nozzle connected with the outlet of the conveying path for spraying the mixture into the tank.    USE - The anaerobic digester is useful in a biogas production equipment (claimed) for producing biogas from organic mixture such as food wastes, agricultural and stockbreeding products and wastewater sludge, where the biogas is bio methane.    ADVANTAGE - The anaerobic digester has improved anaerobic digestion efficiency.    DETAILED DESCRIPTION - The anaerobic digester comprises a space portion located in a receiving tank for receiving a mixture containing an organic mixture and anaerobes, a stirrer stirring the mixture in the receiving tank, an inlet introducing the mixture into the receiving tank, an outlet discharging the effluents from the receiving tank, a filtration unit located within the receiving tank for filtering the mixture in the tank, a containment vessel including a side wall, a conveying path formed along the fluid portion between the inlet and the outlet, a spray nozzle connected with the outlet of the conveying path for spraying the mixture into a digester, two mutually different radius circular injection pipes that are interconnected with each other and placed in the digester for generating biogas, and a gas outlet connected with the receiving tank for discharging biogas through anaerobic digestion. A gas inlet is connected within an inlet port of the tank. The gas outlet is connected with an outlet port of the tank. A microorganism feeder is installed on the circular path for supplying anaerobes into the tank for anaerobic fermentation. A mixed liquor suspended solids (MLSS) measurement device is installed on the circular path for measuring concentration of the MLSS of the tank. A buffer tank is additionally connected with the digester for storing dissolved gas and residual volatile organic acid. An emergency vent is located in an inner portion of the tank for discharging the mixture and removing the precipitating material remaining in the tank to the outside during emergency. The gap between the filter units are maintained with distance of 100 mu m. The injection angle of the injection nozzle is controlled. The injection nozzle automatically measures the surface angle of the surface of the mixture within the tank. The injection pipe sprays the mixture on the surface based on the surface angle this is measured with respect to the tank in vertical direction.