Abstract: A modified metal oxide particle material includes: 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 is adhered to the surface of the metal oxide particle material. 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. 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.