It is intended to provide a novel chondroitin sulfate/dermatan sulfate hybrid chain having biding activity toward a variety of growth factors, neurite outgrowth-promoting activity, and anticoagulant activity and to provide a composition for neurological disease treatment. The novel chondroitin sulfate/dermatan sulfate hybrid chain was separated and purified from the bodies of fishes other than bony fishes. When shark skin is used, the hybrid chain comprises a disaccharide GlcUA(2S)-GalNAc(4S) and has an average molecular weight of 65 to 75 kDa, and the degree of sulfation per disaccharide molecule falls within the range of 0.7 or more to less than 1.20. The hybrid chain is capable of binding to a variety of growth factors and further possesses neurite outgrowth-promoting activity and anticoagulant activity.