A vacuum cleaner includes a cleaner body; a suction part touching a surface to be cleaned, the suction part drawing-in contaminants on the surface to be cleaned; an extension pipe connected the suction part; and a flexible hose connecting the extension pipe with the cleaner body, wherein the flexible hose comprises: a bellow pipe wall with a plurality of peaks (11) and valleys (13); and an auxiliary peak (11b) and an auxiliary valley (11a) formed in each of the plurality of peaks (11). A noise decreasing part (13a) is formed at an inner surface of the valley (13). The structure of the flexible hose prevents the flexible hose from deforming and decreases the friction noise of the fluid.