To provide an abnormal noise preventing agent for preventing the creaking noise expected to occur upon contact of a polyurethane foam with a metal surface with an oily deposit thereon, such as of a rustproof oil or grease, and to provide an abnormal noise preventing method using the same.

The abnormal noise preventing agent comprises a mixed solution wherein the effective ingredient of an anionic surface active agent accounts for 3.5-8.5%, the effective ingredient of a water-soluble wax emulsion accounting for 1.0-3.5%, and pH is adjusted to be 8.0-9.5. In the abnormal noise preventing method for preventing the creaking noise ascribable to the contact between a dried oily thin film on a metal surface and a polyurethane foam, the abnormal noise preventing agent is applied to the metal surface carrying the dried oily deposit, and the dried oily thin film is thereby emulsified or absorbed by the agent for conversion into a hydrophilic emulsion or into a liquid substance which are nonviscous and not water-repellent.