A filling device for a lower foundation of a bottom plate of a Wiggins gas holder comprises a Wiggins gas holder bottom steel plate and a bituminous mortar tank, wherein a hole is formed in the centerof the Wiggins gas holder bottom steel plate, and a connecting sleeve is arranged in the hole; a lower body of the connecting sleeve is welded to the hole in the center of the Wiggins gas holder bottom steel plate; inner threads are formed in the inner upper end of the connecting sleeve; the bottom part of a filling device assembly is rotatably connected to the connecting sleeve through the innerthreads; the upper part of the filling device assembly is connected to the bituminous mortar tank through a mortar conveying hose; the filling device assembly is connected to a vacuumizing device assembly which is arranged at one side of the filling device assembly. With the adoption of the device, gaps between the Wiggins gas holder bottom steel plate and the foundation can be effectively filled; the mobility of bituminous mortar and the gravity of bituminous mortar are utilized; and moreover, bubbles can be removed in vacuum condition, so that the bituminous mortar is effectively full.