To provide a wood preservative composition low in metal corrosiveness containing an effective component different from a conventional wood preservative and having a strong wood preservative effect, a method for preserving wood against decay and wood subjected to preservative treatment.

The wood preservative composition low in metal corrosiveness containing at least one kind of a quaternary ammonium salt compound such as didecyldemethyl ammonium adipate or the like, the method for preserving wood against decay and the wood subjected to preservative treatment are disclosed. The wood preservative composition low in metal corrosiveness contains at least one kind of a triazole compound selected from quaternary ammonium salt compounds such as didecyldimethyl ammonium adipate or the like and at least one kind of an existing wood preservative component such as an iodine compound or the like.