The invention discloses a biogas tank in the technical field of biogas production equipment. The biogas tank comprises a tank body, a stirring mechanism and a driving mechanism, wherein the tank bodyis communicated with a feeding pipe, the feeding pipe comprises an inclined pipe and a vertical pipe which are sequentially communicated, and one end of the inclined pipe is communicated with the tankbody; the stirring mechanism includes a liquid inlet pipe, a hollow disc and a rotating shaft; the driving mechanism includes a driving rod, a first connecting rod, a second connecting rod and a gearconnected at the bottom of the driving rod in a sleeve mode, one end of the second connecting rod is connected with a liquid storage portion, the top of the liquid storage portion is provided with anopening, and a first gap is left between the bottom of the liquid storage portion and the inner wall of the disc; the liquid storage portion is located in the disc, the opening is located under the other end of the rotating shaft, the first connecting rod is in sleeve connection with a bevel gear, the bevel gear is meshed with the gear, and a second gap is left between the bevel gear and the inner wall of the rotating shaft. When raw materials are stirred, a bacterial liquid can be mixed into the raw materials.