To obtain a nutritive auxiliary agent for a crop, having activities for promoting growth of the crop, capable of improving resistance to a disease, and sugar content, taste, etc., of a fruit, and useful for scatter on the surface of leaves and fruit, a soil culture, a water culture by formulating saccharides containing fructose with vinegar.

This nutritive auxiliary agent is obtained by formulating saccharides containing fructose (preferably ≤50 wt.% concentration), such as a mixture, etc., of one or more kinds selected from a crystalline fructose, an isomerized liquid sugar syrup, an inverted sugar type liquid sugar syrup, honey, a degradation product of the fructose and polysaccharides, and condensate of watermelon juice, with one or more kinds selected from a fermented vinegar, a synthesized vinegar and an acetic acid aqueous solution. Preferably, the applying concentration of the nutritive auxiliary agent is ≤2% as the concentration of the saccharides containing the fructose and ≤0.5% as the acidity expressed in terms of the acetic acid.