The present invention is to provide a process for producing a dispersion of fine core/shell type metal oxide particles and the dispersion thereby produced, the present invention are a process for producing a dispersion of fine core/shell type metal oxide particles comprising the steps of mixing a metal salt and a polymer in an organic solvent to obtain a mixture and heating this mixture under reflux at a prescribed temperature to precipitate metal oxide, wherein the metal salt is a nitrate salt or acetate salt and the particle diameter of the fine core/shell type metal oxide particles is adjusted using the molecular weight of the polymer, and a dispersion of fine core/shell type metal oxide particles obtained by the process, which does not undergo sedimentation even after standing for at least one day, and exhibits long-term stability, and a powder thereof.