To provide a small-sized cyclone separator in which a dimension of an axial direction is small and the dust separation efficiency is excellent.

This cyclone separator has a cyclone chamber 3 provided with an air suction port 4 at one end of an axial direction and a discharge port 5 at the other end. The air suction port 4 is formed into an annular region around a suction cutting-off region 10, by providing the suction cutting-off region 10 cutting off air sucking to the cyclone chamber 3 at a prescribed region near the shaft center. The discharge port 5 is formed as a region near the shaft center facing the suction cutting-off region 10. The air suction port 4 formed as the annular region is disposed with tilted blade members 6 for introducing a vortex flow into the cyclone chamber 3 in the circumferential direction. The suction cutting-off region 10 is set to a size of 50% or more of the discharge port 5.