A fiber structural body includes fibers and a fibroin which binds the fibers, and when the fibers are represented by A, and the fibroin is represented by B, the following formulas (1) and (2) are satisfied. 0.03≤volume average particle diameter of B/average width of A in short direction≤4.00  (1) 0.01≤dry mass of B with respect to total mass of fiber structural body/(dry mass of A with respect to total mass of fiber structural body+dry mass of B with respect to total mass of fiber structural body)≤0.40  (2)