A material for adhesion prevention can be adhered to biological tissue with certainty and has improved tissue adhesiveness and biodegradability. Such material for adhesion prevention is composed of: a 1- to 1,000-μm-thick water-soluble support layer comprising a water-soluble polymer； and a 1- to 1,000-μm-thick adhesion prevention layer comprising a biodegradable polymer. The biodegradable polymer has a structure in which a branched polyalkylene glycol comprising 3 to 8 terminal hydroxyl groups per molecule is bound to a polyhydroxy alkanoic acid, and a mass ratio of the branched polyalkylene glycol relative to the total mass is 1% to 30%.
