A cyclone-type dust-collecting apparatus for use in a vacuum cleaner has a cyclone body having an inflow port and an outflow port, the cyclone body being capable of forming a whirling air current from dust-laden air drawn into the vacuum cleaner through the inflow port; a dust-collecting chamber being removably connected with the cyclone body, for collecting dust separated from the drawn air in the whirling air current; and a grill assembly disposed at the outflow port of the cyclone body for preventing a reverse flow of dust through the outflow port of the cyclone body. The grill assembly has a first grill member having a supporting portion supported on the outflow port of the cyclone body; a second grill member removably connected to a lower opening of the first grill member; and a grill portion provided to define a passage in fluid communication with the outflow port in an outer circumference of the second grill member.