The invention discloses a buried type ring main unit comprising an outer cover and a load switch box, wherein the load switch box is arranged at the upper side in the outer cover and is in an all-sealed structure; a switch mechanism is arranged in the load switch box; the load switch box is filled with an SF6 insulating gas; an operation mechanism connected with the internal switch mechanism is arranged outside the load switch box and is provided with a main shaft; the top of the load switch box is provided with a barometre, a gas charging valve and an inlet-outlet line sleeve; the upper partof the rear side of the load switch box is provided with a pressure release valve; a sealing operation device is arranged outside the operation mechanism; and a transparent sealing cover is arranged outside the barometre. The buried type ring main unit can keep sealed during operation, insulate pollutants, i.e. external water vapors, sewage, and the like; and parts, i.e. the outer cover, the loadswitch box, a sealed shell, and the like, are made of stainless steel materials which have high corrosion resistant capability. The invention has good sealing property, high corrosion resistance and long service life and can be directly placed in damp and severe environments, such as a wet mud pit, a cable pit, a basement, and the like, for use and ensure stable electricity supply.