To protect a screw member body 2 by effectively utilizing a cover 3 to prevent intrusion of water or the like into the screw member body 2.

A screw member 1 includes: a screw member body 2 connected to a connected member 7; and a cover 3 with one end of both ends of a cylindrical wall part 8 provided with a closed part 9 and the other end provided with an opening part 10. The cover 3 is put on an end part 5 provided to the screw member body 2, the end part 5 of the screw member body 2 is inserted into an inner side of the cylindrical wall part 8 from the opening part 10, and the end part 5 of the screw member body 2 and the inner side of the cover 3 are connected with each other by screwing female and male screw parts (a male screw 5a and a female screw 8a) together. In this state, a seal part 11 that can brought into pressure contact with the connected member 7 is provided to a periphery of the opening part 10 of the cylindrical wall part 8, so that the inner side of the cylindrical wall part 8 can be blocked from the outside of the cover 3 by the seal part 11. In the screw member body 2, the end part 5 has a stepped part 6 that has a stepped shape with respect to a shaft part 4 and that can be brought into pressure contact with the connected member 7, and the stepped part 6 is juxtaposed to the seal part 11 on the inner side of the seal part 11.