Provided are: an intermediate for preparing metal oxide nanoparticles modified by a surface-modifying group having various molecular structures; surface-modified metal oxide nanoparticles chemically modified by said intermediate; and a method for producing said surface-modified metal oxide nanoparticles. Disclosed are: an intermediate for surface-modified metal oxide nanoparticles that is capable of preparing surface-modified metal oxide nanoparticles in which at least a portion of the surface of each metal oxide nanoparticle is modified by a surface-modifying group, wherein the surface-modifying group has formula (1) as a partial structure thereof; and surface-modified metal oxide nanoparticles prepared from said intermediate. Formula (1): -Ar1-R1-X (wherein: Ar1 represents an aromatic ring in which 3 to 20 atoms constitute the ring skeleton, or a structure in which a plurality of said aromatic rings have been directly bonded; R1 represents a direct bond or a C1-20 alkyl group; X represents -OH, -SH, -NH2, -
