A welding joint 10 for a fuel tank reduces the amount of fuel vapor in the fuel tank that escapes into the atmosphere. The fuel tank welding joint 10 a joint main body 20 and a barrier layer laminated on the surface of the joint main body 20. The joint main body 20 is formed of a first resin material weldable to the wall of the fuel tank FT, and the barrier layer 30 is formed of a second resin material that is adhesively and chemically reactive with the first resin material and that is more fuel-impermeable than the first resin material. An end portion 34 formed so as to be exposed to the outside at the end of a tube portion 24 is formed on the barrier layer 30. When the barrier layer 30 is injection molded on the surface of the joint main body 20, the end portion 34 is formed by the flow of the second resin material through the end of the tube portion 24 to increase the adhesive strength of the end face where the parts are joined.