PROBLEM TO BE SOLVED: To provide an antifogging agent excellent in preventability of a haze and a water drop generating on a film and a sheet from forming, having high effects on various bacteria typified by Gram-negative bacteria and easily controlled in pH and to provide a packaging material capable of significantly improving freshness and storing durability of contents. SOLUTION: The antifogging agent comprising an &epsi-polylysine and/or a salt thereof is produced and added and/or adhered to the packaging material.