A dusting device to be rotatably connected to the bottom of a cleaning machine or vacuum cleaner includes a rotary disc and a dusting element. The rotary disc includes a base and a connecting portion below the base. The connecting portion extends outward from the periphery of the base and has a bottom surface forming a pressing plate. The dusting element is detachably assembled to the connecting portion of the rotary disc in order to be pressed by the pressing plate. The dusting element includes at least one cleaning layer for contact with a surface to be cleaned so as to carry out dusting and cleaning.