Disclosed is a wood preservative which contains as the active ingredient 3'-isopropyl-2-trifluoromethyl benzoic acid anilide, expressed by the formula (I)； further disclosed is a wood processing method which uses said preservative. Provided are a wood preservative and a wood processing method which have an excellent low-dose preservation property with respect to various types of wood-rotting fungi, and which are economical and have a small environmental load.
