To obtain a solubility improving agent capable of improving the solubility of a water-insoluble food additive by including hydroxyl group.

The objective solubility improving agent for a water-insoluble food additive is produced by including hydroxyl group into the agent. Ethyl alcohol is soluble in water, however, the active component of a food additive soluble in ethyl alcohol is not necessarily soluble in water or a water-soluble solution. The food additive containing an active component soluble in ethyl alcohol is mixed to a water-soluble food additive or food material and homogeneously formulated to a food, drink or food material without causing the precipitation and deposition. In addition to ethyl alcohol, alcohols having carbon number of ≤3 are soluble in water. Accordingly, the mixing and dissolution performance of a water-insoluble food additive to a food additive or food material dissolving water-containing or water-soluble active component is improved by the aid of a substance having hydroxyl group as a function to dissolve in water.