To provide a fiber structure for reinforcement improved so that high adhesiveness to molding resins is obtained and a fiber-reinforced resin composition containing the fiber structure.

A cellulose producing bacterium is cultured in the surface and/or surface layer of the fiber structure or bacteria cellulose is applied to the surface and/or surface layer of the fiber structure. As a result, the bacteria cellulose is attached to the surface and/or the surface layer of the fiber structure and permeated therein to improve adhesiveness between the molding resin and the fiber structure for reinforcement. Such fiber structure is used as a reinforcing material for thermoplastic or thermosetting molding resins to provide a molding material of the fiber-reinforced resin composition or its molded article.