There is provided a method of manufacturing a refractive index distribution structure having a plurality of microparticles, suppressing density unevenness between the plurality of microparticles, capable of obtaining uniform in-plane characteristics, and capable of maintaining stability and high reproducibility. The method of manufacturing a refractive index distribution structure includes manufacturing a plurality of core-shell microparticles including a shell and a core microparticle contained in the shell, the core microparticle being made of a material having a refractive index higher than the material forming the shell and having the same core diameter, and the shell having a different shell thickness; and forming a refractive index distribution structure by arranging the plurality of core-shell microparticles on a substrate.