A packaged blood purification device including a hollow fiber blood-processing device having a bundle of hollow fibers and a cylindrical container holding the bundle of hollow fibers; and a gas-impermeable container for packaging the hollow fiber blood-processing device. The hollow fiber blood-processing device is sealed together with an oxygen absorber in the gas-impermeable container, and is sterilized with radiation. The blood-processing device is produced by a method including the steps of sealing a hollow fiber blood-processing device in said gas-impermeable container together with an oxygen absorber, and radiation sterilizing the blood-processing device held in the sealed gas-impermeable container.