The invention provides a negative electrode material for a sodium secondary battery, which can exhibit excellent cycle properties while keeping a high discharge capacity; a method for producing the negative electrode material; a negative electrode for a sodium secondary battery; and a sodium secondary battery. The negative electrode material for a sodium secondary battery according to the present invention comprises a suiflde or a sulfide complex each of which contains sulfur and antimony and may additionally contain a component (i) if necessary: (i) at least one element selected from the group consisting of Sn, As, Bi, Ge, Ga, Pb and C. When the component (i) is contained, the contents of the above-mentioned components are as follows: sulfur: 10-70 mol%; antimony: 10-70 mol%; and (i): 3-60 mol%.