Magnetic beads were developed for the purpose of applying to biological use. The beads were composed of magnetite particles coated with amylose which showed the affinity bonding with maltose binding protein. The beads showed superior response to magnetic field based on the high magnetization and superior dispersability after the removal of magnetic field in the process of purifying a protein from biological samples. The beads showed five times greater efficiency in purification of protein than amylose resin beads currently on the market.