A dust collector includes a base, a cover, and a barrel disposed between the base and the cover. The barrel includes a lower frame, an upper frame, one or more intermediate frames, and one or more telescopic tubes selectively secured to the frames, to form a spatial structure for the barrel, and the barrel is collapsible to a collapsed structure when the telescopic tube is disengaged from the lower and the upper and the intermediate frames. The intermediate frames may be received within the upper frame, and the lower frame may be received in the intermediate frames. The dust bag may be attached to the barrel with hooks or catches or clamping rings.