The utility model discloses a tank cleaning device for cleaning a tank to be cleaned. The tank cleaning device comprises a base, a spray gun driving device and a spray gun, wherein the base is used as a basic support piece of the tank cleaning device and is arranged at the lowermost part of the tank cleaning device; the spray gun driving device is mounted on the base and has a plurality of motion freedom degrees; the spray gun driving device comprises a spray gun lifting driving device which is vertically arranged on the base, a spray gun telescopic driving device which is horizontally arranged on the spray gun lifting driving device, a spray gun rotation driving device which is arranged at the end part of the spray gun telescopic driving device and a spray gun swinging driving device which is vertically arranged on the base and is connected with the spray gun lifting driving device; the spray gun is used for spraying supersonic speed air flow and is mounted on the spray gun driving device. Residual slag and residual liquids adhered to or solidified in a tank can be efficiently and rapidly cleaned through a supersonic speed jet generated by high pressure oxygen and the reaction between oxygen and residual iron, so that the tank cleaning device is safe and reliable, convenient to operate and high in slag cleaning efficiency.