A box body (11) includes a plurality of terminal plates (14) arranged in the box body (11), and a cable introduction portion (13) disposed on a side surface of the box body (11) to introduce a connection cable (20). A water blocking sleeve (30) is disposed around the connection cable (20) to secure the connection cable (20) to the cable introduction portion (13). The water blocking sleeve (30) is disposed between the cable introduction portion (13) and the connection cable (20). The water blocking sleeve (30) includes an inner sleeve (31) in close contact with the connection cable (20), and an outer sleeve (32) disposed on an outer side of the inner sleeve (31) and being in close contact with the cable introduction portion (13). The inner sleeve (31) and the outer sleeve (32) are integral with one another.