The present invention provides a pharmaceutical agent having high safety and a neurotrophic factor-like activity, which contains, as an active ingredient, any one compound included in fatty acids each having 8 carbon atoms (C8) or having 10 carbon atoms (C10) to 12 carbon atoms (C12) or fatty acid esters thereof, such as 3 , 7-dimethyloctanoic acid ethyl ester, geranic acid ethyl ester, and the like, each of which has 8 carbon atoms (C8), decanoic acid methyl ester, trans-2-decenoic acid, trans-2-decenoic acid methyl ester, trans-2-decenoic acid ethyl ester, trans-2-decenoic acid-2-decenyl ester, trans-2-decenoic acid cyclohexyl ester, trans-2-decenoic acid isopropyl ester, trans-3-decenoic acid methyl ester, trans-9-decenoic acid methyl ester, and the like, each of which has 10 carbon atoms (C10), trans-10-undecenoic acid methyl ester, trans-10-undecenoic acid ethyl ester, and the like, each of which has 11 carbon atoms (C11), and dodecanoic acid, and the like, each of which has 12 carbon atoms (C12), or salts thereof or prodrugs thereof.
