An oxygen-barrier film and an adhesive used therefor. Provided are an adhesive, which can be used for packaging foodstuffs and contains mainly a polyester having excellent oxygen-barrier properties, and an oxygen-barrier film that uses the adhesive. The oxygen-barrier film is prepared using an adhesive that includes: an amorphous polyester polyol, which is obtained by polycondensation of a polyvalent carboxylic acid component including at least one type of ortho-oriented aromatic dicarboxylic acid or anhydride thereof, and a polyhydric alcohol including at least one compound selected from the group consisting of ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol and cyclohexanedimethanol, and a curing agent capable of reacting with the amorphous polyester polyol.