A mannan and water-soluble glucans from Dictyophora indusiata, a water-insoluble glucan from Ganoderma japonicum, a galactomannan from Cordyceps cicadae, and acidic heteroglycans from Auricularia auricula-judae and Auricularia species (Yu er), whose structural features have been reported in our previous papers of this series, were tested for antitumor activity against subcutaneously implanted sarcoma 180 in mice by intraperitoneal administration. Considerable antitumor activity was observed with partially O-acetylated (1→3)-α-D-mannan (T-2-HN) at doses of 10 mg·kg^-1·d^-1×10, water-soluble (1→3)-β-D-glucans having β-1→6 linked D-glucosyl side chains (T-4-N and T-5-N) at doses 5 or 10 mg·kg^-1·d^-1×10, and a glucuronoxyloglucomannan (U-3-A) at doses of 25 mg·kg^-1·d^-1×10.