A dust collector for a vacuum cleaner disclosed herein includes a first cyclone to separate dust from air introduced from a lower portion thereof with containing foreign materials and discharge the separated dust into a first dust storing unit, a second cyclone configured to separate fine dust from the air, from which the dust has been separated by the first cyclone, and discharge the separated fine dust, a second dust storing unit that is provided in the first cyclone, and located in a second case to collect therein the fine dust discharged from the second cyclone, and a lower cover to define a bottom surface of the first dust storing unit, the second dust storing unit and the first cyclone upon being closed, and discharge therethrough the foreign materials collected in the first dust storing unit, the second dust storing unit and the first cyclone upon being open.