A weld joint having a base material and a weld metal both of an austenitic steel, wherein the weld metal has a chemical composition, in mass %, that C: 0.04% or less, Si: 1.0% or less, Mn: 3% or less, P: 0.02% or less, S: 0.005% or less, Cr: 15 to 25%, Ni: 30% or more, Mo: 10% or less, Nb: 2.5 to 5%, Al: 3.0% or less, Ti: 0.5% or less, and the balance: Fe and inevitable impurities, the contents of Al and Ti satisfying the following: (Ti+Al)>Nb/8. The weld joint is a high strength austenitic steel weld joint which exhibits excellent toughness at a low temperature and excellent resistance to hydrogen embrittlement, which are required for a piping and a vessel for high pressure hydrogen, particularly also in a welded zone.