A cyclone technology for a vacuum cleaner--axial inlet flow cyclone and the tangential inlet flow cyclone-- to collect dusts efficiently and reduce pressure drop has been studied experimentally. The optimal design factors such as dust collection efficiency, pressure drop, and cut-size being the particle size corresponding to the fractional collection efficiency of 50% were investigated. The particle cut-size decreases with reduced inlet area, body diameter, and vortex finder diameter of the cyclone. The tangential inlet twin-flow cyclone has good performance taking into account the low pressure drop of 350 mmAq and the cut-size of 1.5 μm in mass median diameter at the flow rate of 1 m3/min. A vacuum cleaner using tangential inlet twin-flow cyclone shows the potential to be an effective method for collecting dusts generated in the household.