To enable to surely carry out water-stopping treatment of grounding wires in a simple operation without greatly increasing a volume of wire terminal parts.

A base 2 with a recess part 4 formed large enough to accommodate suction terminals of a plurality of grounding wires 40 in a bundle, and a lid body 3 forming a decompression room S in which the plurality of suction terminals are sealed inside by closing openings of the recess part 4 in free detachment while pinching and pressing an intermediate part of the plurality of grounding wires 40 accommodated in the common recess part 4. At least either the base 2 or the lid body 3 is provided with a suction channel capable of communicating the decompression room S and a suction pump P.