The present invention relates to a nonaqueous external preparation composition comprising a basic drug or a salt thereof dissolved in a fatty acid-based ionic liquid, wherein the basic drug has at least one tertiary amino group, and the fatty acid-based ionic liquid is an equimolar salt of a fatty acid selected from the group consisting of levulinic acid, oleic acid, and capric acid, and an organic amine compound selected from diisopropanolamine or diethanolamine.