Starch sugar compositions comprising a plurality of nigerooligosaccharide alcohols may be added to food and drink as at least part of its sweeteners, whereby various advantages can be provided, eg not only a sweetness can be imparted, but also the quality of sweetness can be improved, and the moisture retention of foods can be improved. The nigerooligosaccharide alcohols may be prepared by allowing at least one enzyme selected from a -amylase of various types, an oligosaccharide-forming amylase, a beta -amylase and a debranching enzyme and an enzyme capable of forming nigerooligosaccharide by transglycosylation and/or condensation reaction to act successively or simultaneously on a material comprised of at least one selected from i) starch, ii) a maltooligosaccharide with a degree of polymerization not lower than maltose and iii) a dextrin, to form nigerooligosaccharide, which is thereafter reduced to obtain a starch sugar composition containing the nigerooligosaccharide alcohol(s).