To provide a method for producing a three-dimensional fiber structure, by which a laminated fiber layer comprising filaments is formed in a plate-like form having a bent portion, and the three-dimensional fiber structure in whose portions except the bent portion of the laminated fiber layer thickness-directed fibers are arranged can simply be produced in a state free from wrinkles and stains.

In a process for arranging filaments, fiber layers formed by arranging filaments 12 to be engaged with pins and turned back are laminated to form an at least biaxially oriented laminated fiber layer 13. In the process for arranging filaments, filaments 12 arranged on the outside of a place for forming a bent portion 15 are arranged in a loosed state in response to a route difference between the inside and outside of the bent portion 15. In a process for inserting the thickness directed fibers, the thickness directed fibers 14 are inserted into the laminated fiber layer 13 to cross the laminated fiber layer 13 to form a flat plate-like primary structure 21. In a bending process, the bent portion 15 is formed at a prescribed position of the primary structure 21.

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