To provide a composite material having inorganic particles dispersed in a resin matrix, wherein even when using ultra-fine inorganic particles with an average particle size of less than 100 nm for fine adjustment to its physical properties, the composite material expresses a structural color, and the composite material does not use a pigment or the like and shows excellent color tone compatibility in dental composite resin repair.SOLUTION: A composite material contains, as inorganic particles, inorganic spherical particles having a specific average primary particle size, an extremely narrow particle size distribution width, and a larger refractive index than that of a matrix resin, and ultra-fine inorganic particles. A dispersion dynamic state of the inorganic particles evaluated in radial distribution functions satisfies such conditions that: an inter-particle distance of the closest particles is once to twice an average particle size of the inorganic spherical particles, and a minimum value between the inter-particle distance of the closest particles and the inter-particle distance of second closest particles is 0.56 to 1.10.SELECTED DRAWING: Figure 2【課題】 樹脂マトリックス中に無機粒子が分散してなる複合材料であって、物性微調整のために平均粒径が１００ｎｍ未満の超微細無機粒子を用いた場合であっても、構造色を発現し、顔料等を用いることなく、歯科用コンポジットレジン修復において優れた色調適合性を示す複合材料を提供する。【解決手段】 無機粒子として、特定の平均一次粒子径を有し、粒度分布幅が極めて狭く、且つマトリックス樹脂よりも大きな屈折率を有する無機球状粒子と、超微細無機粒子と、を含み、動径分布関数で評価される無機粒子の分散動状態が、最近接粒子間距離が無機球状粒子の平均粒子径の１倍以上２倍以下となり、且つ、最近接粒子間距離と次近接粒子間距離との間における極小値が０．５６以上１．１０以下となる条件を満足するようにする。【選択図】図２
