Abstract: A three-dimensional structural member adapted for wide use as an industrial composite structural member such as an aircraft or other vehicle interior part. A reinforcing substrate fabric has a plurality of planar structural sections. The reinforcing substrate fabric serving as a core material is impregnated or covered with a shape retention agent such as synthetic resin or ceramic material and then solidifed to form a predetermined three-dimensional structure or, alternatively, the reinforcing substrate fabric is unfolded to form a predetermined three-dimensional structure and then impregnated or covered with the shape retention agent. The three-dimensional structural member is characterized in that the reinforcing substrate fabric is formed of lengthwise continuously arrayed yarns. Fabric areas defined by a plurality of surfaces using a plurality of groups of yarns are integrally formed.