Welding connector for a fuel tank

Welding connector has a cylindrical portion which is a connecting portion and an annular fusion welding area is fixed to a base end portion of the cylinder portion, wherein the fusion welding area is formed so that it can be thermally fusion-welded to a synthetic resin-made fuel tank. At least parts of the fusion-welded portion and the cylinder portion are formed integrally by using a resin-alloy material in which a high-density polyethylene, which is obtained by introducing a functional group of high affinity for a hydroxyl group of the ethylene-vinyl alcohol copolymer, is alloyed with the ethylene vinyl alcohol copolymer alone or together with the high-density polyethylene.