Austenitic stainless steel material

To provide an austenitic stainless steel material having a high creep strength and a high creep ductility even in a high-temperature environment at 800° C. or more. An austenitic stainless steel material according to the present disclosure has a chemical composition that includes, in mass %: C: 0.060% or less; Si: 1.0% or less; Mn: 2.00% or less; P: 0.0010 to 0.0400%; S: 0.010% or less; Cr: 10 to 25%; Ni: 25 to 45%; Nb: 0.2 to 2.0%; W: 2.5 to 6.0%; B: 0.0010 to 0.0100%: Al: 2.5 to 4.5%; and the balance being Fe and impurities, and satisfies Formulae (1) and (2), and the sum of the content of dissolved Nb and the content of dissolved W is 3.2 mass % or more.(W/184+Nb/93)/(C/12)≥5.5 (1)(W/184+Nb/93)/(B/11)≤450 (2)In Formulae (1) and (2), the content in mass % of the corresponding element is substituted for each symbol of element.