PROBLEM TO BE SOLVED : To establish a novel screening method for the purpose of searching for an effective component as a color tone improving agent for the skin based on a novel mechanism of action.SOLUTION : Disclosed are a method for screening a color tone improving agent for the skin using the activity of a differentiation associated factor in a cell and/or an intracellular vesicle delivery associated factor as an indicator, and a composition containing a material determined as improving a color tone of the skin.