By using electron-beam-induced graft polymerization, an epoxy-group-containing monomer, glycidyl methacrylate (GMA), was appended onto a 6-nylon fiber; subsequently, N-methylglucamine as a chelate-forming moiety was added to the epoxy group. The chelating group density of the resultant chelating fiber was 2.0 mmol/g, which was 74% of that of a commercially available chelating bead containing the same functionality. A 150 mg-B/L boron solution was forced to flow through the chelating-fiber-packed bed at the space velocity range from 10 to 100 h(-1), defined by dividing flow rate by bed volume (0.3 mL). At a space velocity of 20 h(-1), the dynamic binding capacity of the chelating-fiber-packed bed was 2.5-fold higher than that of the chelating-bead-packed bed.