A cleaning brush structure is applicable for a washing machine, and the washing machine contains: a body in which an external drum is mounted, and the external drum accommodates an internal drum having a plurality of through orifices. Each of the plurality of through orifices accommodates a cleaning brush which includes a fixing element and a brushing element, and the fixing element has a conical face formed on a peripheral wall thereof, a small-diameter segment arranged on a first end thereof, and a large-diameter segment arranged on a second end thereof opposite to the first end of the fixing element. The brushing element is mounted on the small-diameter segment of the fixing element and has bristles inserted through said each through orifice so that the fixing element is fixed in said each through orifice of the internal drum.