Particle material and manufacturing method therefor, and transparent resin composition

A particle material comprising

• an aggregate used so as to be dispersed in a transparent resin material,
• the aggregate including primary particles in which a specific surface area diameter based on a surface communicating with outside is not less than 0.8 nm and not greater than 80 nm, the primary particles formed of an inorganic substance in which a composition of a surface and a composition of an inside are different from each other,
• the aggregate beings formed by binding and fusing particles through dehydration and condensation, wherein
• a volume average particle diameter in the aggregate is greater than 0.1 μm,
• the composition of the surface has a refractive index different from that of the composition of the inside,
• an existence ratio between the composition of the surface and the composition of the inside is determined such that a hardened product which is obtained by dispersing and hardening 10 parts by mass of the aggregate in 100 parts by mass of the transparent resin material and which has a thickness of 2 mm, has a transmittance (wavelength 400 nm) of not less than 80%,
• the primary particles each have the inside formed of boehmite or γ alumina and the surface formed of silica, and
• the particle material does not include a particle material in which a volume average particle diameter is not less than 6 nm and not greater than 0.2 μm.