According to the present invention there is provided a method for producing an anti-adhesion material that is constituted of a thermally crosslinked gelatin film, and has a water content of 60 to 85% calculated by the following formula : water content (%) = [(Ws-Wd)/Ws] x 100 (%) in which Ws represents a weight (wet weight) of the anti- adhesion material immersed in a phosphate buffered saline solution at a temperature of 25°C for one hour, and wd represents a weight (dry weight) of the anti-adhesion material dried completely using a vacuum drying apparatus(1), said method comprising a step of thermal crosslinking under a reduced pressure (1Torr or less) at a temperature of 120 to 170°C and for 30 minutes to 72 hours, of a non-crosslinked gelatin film(2), sandwiched between two sheets(3) having the same thermal conductivity.
