Disclosed herein are a functional-substance-including structured material having good dispersion stability, and an ink composition, which inhibits aggregation by interaction between particles, and has stable dispersibility in a solvent and good coloring ability and fixing ability. The functional-substance-including structured material comprises a plurality of functional substances different from each other physically included in a block polymer or graft polymer. The ink composition comprises the functional-substance-including structured material, and a solvent or dispersing medium.