The utility model discloses a level gauge, including pipe, anticorrosion floater and a plurality of magnetic red node modules of anticorrosiving, install on the inner wall of pipe that anticorrosives each magnetic red node modules and each magnetic red node modules's the line body all is located and anticorrosives intraductally in proper order along the axial direction of the pipe that anticorrosives, and the central point of anticorrosion floater puts and sets up the hole of running through of cup jointing, and the anticorrosion floater inlays along the circumference direction of cup jointing the hole pore wall and is equipped with many magnetic stripes, and the anticorrosion floater cup joints the borehole jack through it to be established and enclose at the anticorrosion outside of tubes. This level gauge have simple structure compactness, low cost, security high, can show in real time the water level, can the anticorrosion and the anti fraud and the advantage of refusing.