Plane measuring instrument for flatness of building wall

The invention relates to the technical field of building measurement, in particular to a plane measuring instrument for building wall flatness. Comprising a moving frame, the upper side face of the moving frame is rotationally connected with an adjusting frame, the side, away from the moving frame, of the adjusting frame is fixedly connected with symmetrically-distributed electric sliding rails, the electric sliding rails are provided with sliding blocks, the symmetrically-distributed sliding blocks are jointly and fixedly connected with a fixing frame, and the upper side face of the fixing frame is fixedly connected with a lifting frame; the adjusting frame is fixedly connected with the symmetrically-distributed first electric push rods, the telescopic ends of the first electric push rods are rotationally connected with connecting sleeves, and the symmetrically-distributed connecting sleeves are fixedly connected with L-shaped plates. The adjacent L-shaped plates are driven by the first electric push rods to