The present invention is directed to a photoreactive polysaccharide which comprises hyaluronic acid covalently bonded to a glycidyl ester of the photoreactive compound represented by the formula (I):wherein R1-CO- represents a residue of a photoreactive compound having the carboxyl group(s) identified, and an unsaturated carbon double bond, selected from the group consisting of cinnamic acid, thiopheneacrylic acid, cinnamylideneacetic acid and sorbic acid, a photocrosslinked polysaccharide produced by crosslinking the above-mentioned polysaccharide by light irradiation, as well as a medical product comprising the same. Preferably the medical product is an anti-adhesive agent for a substrate for sustained drug release or a substrate for culturing cells.
