A cyclone dust collector is provided, including a cyclone unit that includes a first cyclone unit including a cyclone chamber to separate dust from dust-laden air, and a second cyclone unit, which is mounted in the first cyclone unit, including a plurality of cones to separate fine dust, and a cover unit that is formed on the cyclone unit to gather air discharged from the second cyclone unit and guide the air outside the cyclone dust collector, wherein the first cyclone unit includes a blocking plate at a lower part of the first cyclone unit, the blocking plate including a plurality of holes that are in fluid communication with the plurality of cones.