The fiber structure system of the present invention includes a sheet-like shape of a plurality of first resin fibers, has a plurality of voids, and contains a plurality of first resin fibers in a state where fine particles of tungsten oxide are dispersed. The content of the fine particles of the tungsten-based oxide may be 0.5% by weight or more and 6% by weight or less with respect to the total weight of the plurality of first resin fibers. A high transmittance of visible light can be achieved by dispersing the fine particles of tungsten oxide with light wavelength selective reflectivity through which visible rays can penetrate and infrared rays can be reflected in the plural first resin fibers constituting the fiber structure. With excellent thermal insulation properties.本發明之纖維構造體係包含複數第1樹脂纖維之薄片狀的形狀，具有複數空隙部，並會以讓鎢系氧化物之微粒子分散的狀態下來含有複數各第1樹脂纖維。鎢系氧化物之微粒子含量係可相對於複數第1樹脂纖維的全部重量而為0.5重量%以上，6重量%以下。藉由讓可見光線會穿透而紅外線會反射之具有光波長選擇反射性的鎢系氧化物之微粒子分散於構成纖維構造體之複數各第1樹脂纖維，便可達成可見光線之高穿透率與優異的隔熱性能。
