To obtain a fiber structure having a flexible touch, a good tension and a good stiffness by producing a bacterial cellulose on the surfaces of fibers constituting the fiber structure and subsequently subjecting the product to a fibrillation treatment.

This method for producing a fiber structure having fibrils comprises immersing a fiber structure such as a fujiette produced from rayon filaments in the culture solution of a cellulose-producing bacterium such as a bacterium belonging to the genus Acetobacter, culturing the cellulose-producing bacterium on the surfaces of the fibers to coat the fiber surfaces with the produced bacterial cellulose in an amount of ≥0.1 wt.%, preferably ≥0.2 wt.%, based on the weight of the fibers, and subsequently subjecting the coated fiber structure to a rubbing fibrillation treatment using a washer, a liquid flow dyeing machine, etc.