Abstract: A breather pipe mounted to a fuel tank is divided into an outer pipe and an inner pipe, a flange is integrally formed at an end part of the outer pipe on the tank side, then the flange is projection-welded to a wall part of the fuel tank, ensuring a sealability. An upper end of the inner pipe is inserted and held to a lower end of the outer pipe in the fuel tank, and the outer pipe and the inner pipe are sealed by a sealing member, tapering joint or caulking joint. Thus, the sealability at the joint part is ensured, while enhancing a joint strength without soldering which involves pollution.