An eco-friendly fertilizer that acts as a plant growth promotion agent, soil improvement agent, bactericide and insecticide agent, disease and harmful insect prevention agent and the like, and is suitable for organic farming. The fertilizer contains extract from fruits, leaves, stems, seeds and/or roots of the Yaeyama Aoki and increases the amount of yield and extends the freshness period after harvest when applied to fruits, vegetables, leafy vegetables, root vegetables, grains as well as flowers and shrubs.