Disclosed is a slurry supply device including a nozzle configured to eject slurry, a slurry supply unit configured to receive the slurry from the nozzle and to discharge the slurry through at least one slurry hole, a receiving unit configured to allow the slurry supply unit to be mounted, inserted, seated, coupled, supported, or placed therein so as to enable discharge of the slurry from the slurry supply unit, the receiving unit being configured to receive a flowing material around the slurry supply unit and a slurry protection unit configured to enclose a space for passage of the slurry from an exit of the nozzle to an entrance of the slurry supply unit in conjunction with the flowing material.