Modified metal oxide particle material and method for producing same

A modified metal oxide particle material comprising:

• a metal oxide particle material having, on a surface thereof, a functional group other than a phenyl group;
• and
• a modifying material formed of a silicon-containing compound having a phenyl group, the modifying material being adhered to the surface of the metal oxide particle material, wherein
• when the modified metal oxide particle material is washed with methyl ethyl ketone, a ratio (C/H) of a carbon content C (% by mass) to a surface area H (m2) per 1 g is 0.05 or less after the washing, and the ratio (C/H) is reduced by 0.1 or more, and the modifying material is removed by 50% or more by mass, after the washing compared with before the washing, and the silicon-containing compound of the modifying material is a silane compound having a phenyl group, or a condensation product of a silane compound having a phenyl group and a silane compound having a hydrocarbon group that binds directly to Si.