A metal material which exhibits both excellent workability and excellent metal dusting resistance and which is suitable for use as the material in a cracking furnace, a reforming furnace, a heating furnace, or a heat exchanger in petroleum refining or petrochemical plants or the like. A carburization-resistant metal material characterized by containing by mass C: 0.08 to 0.4%, Si: 0.6 to 2.0%, Mn: 0.05 to 2.5%, P: 0.04% or less, S: 0.015% or less, Cr: 18 to 30%, Ni: 20 to less than 30%, Cu: 0.5 to 10.0%, Al: 0.01 to 1%, Ti: 0.01 to 1%, N: 0.15% or less, O (oxygen): 0.02% or less with the balance consisting of Fe and impurities and by satisfying relationship (1). The material may further contain one or more of Co, Mo, W, B, V, Zr, Nb, Hf, Mg, Ca, Y, La, Ce and Nd. C > 0.062Si + 0.033Cu - 0.004Cr + 0.043 (1) (wherein each symbol of element represents the content of the element in mass%).