The local atomic structures of liquid Sb 40 S 60 , Sb 44 Sb 56 and Sb 90 S 10 were investigated by the neutron diffraction method. The characteristic features of the structure factor, S(q), of liquid Sb 40 S 60 are as follows: (i) a prepeak is observed at around q ¼ 1.2 A ˚À1 , (ii) heights of the first and second peaks in S(q) are similar, (iii) oscillations in S(q) are persisted over the 25 A ˚À1 . The overall feature of S(q) for liquid Sb 44 S 56 is similar to that for liquid Sb 40 S 60 . On the other hand, the feature of S(q) for liquid Sb 90 S 10 is quite different from those of liquid Sb 40 S 60 and Sb 44 S 56 . The prepeak is not observed in S(q) for liquid Sb 90 S 10 while oscillation of S(q) still remains over 20 A ˚À1 . The height of the first peak in S(q) becomes larger than that of the second peak. These results suggest that there exists the shortrange order for these liquid Sb-S mixtures and also exists the middle-range order in the liquid Sb 40 S 60 and Sb 44 S 56 . The local atomic structure of liquid Sb 90 S 10 seems to be quite different from that of liquid Sb 40 S 60 , which can be related to the metal-non-metal transition and the existence of the two-phase region between the composition of Sb 40 S 60 and Sb.