A cyclone dust-separating apparatus includes a cyclone unit having air inflow and air outflow parts that separate dust or dirt from air, the cyclone unit being installed such that a longitudinal axis thereof is substantially horizontally arranged; a dust bin joined to a bottom end of the cyclone unit that collects the dust or dirt separated by the cyclone unit, the dust bin installed in such a manner that a longitudinal axis thereof is substantially perpendicular to the longitudinal axis of the cyclone unit; a nonporous envelope detachably disposed in the dust bin that stores the dust or dirt collected into the dust bin; and a pressure difference-generating passage to communicate an outlet of the air outflow part and the dust bin with each other so as to allow the nonporous envelope to come in contact with an inner surface of the dust bin by a pressure difference between the dust bin and the air outflow part.