Metal oxide nanoparticle, method for producing the same, nanoparticle dispersed resin and method for producing the same

Disclosed is a metal oxide nanoparticle having a surface-modified core/shell structure having an organic functional group in the surface. This metal oxide nanoparticle is characterized in that the element constituting the metal oxide for the core is at least one element selected from group 4 elements and group 5 elements of the periodic table, and the core is obtained by controlling the refractive index. Also disclosed is a nanoparticle dispersed resin containing a matrix resin and the metal oxide nanoparticles dispersed in the matrix resin. The metal oxide nanoparticle is not colored while having high refractive index, and can be uniformly dispersed in a matrix resin without causing secondary aggregation. The nanoparticle dispersed resin obtained by uniformly dispersing the metal oxide nanoparticles in a matrix resin has high refractive index and excellent colorless transparency.