A cyclone unit capable of enhancing dust collection performance. A cyclone unit includes a cyclone unit body, a dust box and a core tube. The cyclone unit body includes a lower base, an upper base and a middle base sandwiched between the lower base and the upper base. The dust box is assembled to the cyclone unit body so as to collect dust and dirt. The core tube, having a meshed shape, is assembled to the middle base so as to be located inside the dust box. The core tube is detachable from the middle base while the upper base is assembled to the lower base.