An object of the present invention is to provide an anti-adhesion material having sufficient in vivo degradability and excellent anti-adhesion characteristics, and also superior to conventional ones in terms of handling properties under wet conditions. The anti-adhesion material (1) of the present invention has a sheet-like base layer (10) containing a water soluble polymer (e.g., pullulan), a first cover layer (20) placed on a surface on one side of the base layer (10) and containing an aliphatic ester, and a second cover layer (30) placed on a surface on the other side of the base layer (10) and containing an aliphatic ester. The optical thickness of each of the first cover layer (20) and the second cover layer (30) is set to be 27 nm or greater and smaller than 160 nm.