It has been found that a limulus-positive glycolipid is present in xanthan gum derived from Xanthomonas, which has been commercially available and eaten for many years, and this was purified, and it has been found that this limulus-positive glycolipid has an immunopotentiation effect. A method for safely and inexpensively producing the limulus-positive glycolipid containing an immunopotentiator at high concentrations is provided. The method for producing the limulus-positive glycolipid of the present invention comprises extracting the limulus-positive glycolipid from xanthan gum. A limulus-positive glycolipid composition containing the limulus-positive glycolipid can be used for various applications such as pharmaceuticals, pharmaceuticals for animals, quasi drugs, cosmetics, foods, functional foods, feedstuff and bath agents.