An object of the present invention is to provide a new substance having innate immune stimulating activity. Provided is a polysaccharide having innate immune stimulating activity, comprising: 25 to 50 parts by mole of galacturonic acid, 15 to 50 parts by mole of galactose, 0 to 7 parts by mole of glucose, 0 to 30 parts by mole of arabinose, 0 to 6 parts by mole of xylose, and 3 to 15 parts by mole of rhamnose as constituent sugars； and a polygalacturonic acid chain as a main chain, having α-1,4-linked galacturonic acid. An innate immune stimulant comprising the polysaccharide as an active component and a food or drink comprising the polysaccharide are also provided.
