The nitrate pyrolysis device comprises a reaction tank, a pyrolysis device and a heating device, wherein the reaction tank is a horizontally arranged hollow cylindrical tank body, the top of the hollow tank body is provided with a nitrate feed port and an exhaust pipe, and the bottom of the hollow tank body is provided with a metal oxide outlet; the pyrolysis device comprises a pyrolysis pipe anda power device, the pyrolysis pipe is a horizontal hollow pipe, the pyrolysis pipe horizontally penetrates through the reaction tank, a plurality of blades are connected to the outer wall of a pipe body, located in the reaction tank, of the pyrolysis pipe, and one end of the pyrolysis pipe is connected with the power device; the heating device comprises a heating element and a heating power supplyconnected with one end of the heating element, and the other end of the heating element is inserted into the pyrolysis tube from the other end of the pyrolysis tube. According to the utility model, continuous pyrolysis of nitrate and industrial continuous operation of nitrogen oxide recovery can be realized, and the defects of material adhesion, complex operation and low oxide recovery rate are avoided.