A used toner collecting device for an image forming apparatus includes a used toner receiver for receiving used toner remaining on a surface of a photoconductive medium, a used toner conveying member for conveying the used toner received in the used toner receiver, and a used toner receptacle for storing the used toner conveyed by the used toner conveying member. The used toner conveying member includes a used toner conveying auger mounted in the used toner receiver along a lengthwise direction of the used toner receiver, a casing disposed between the used toner receiver and the used toner receptacle, and a used toner conveying belt running in the casing. The used toner conveying belt has projecting wings arranged at intervals on an outer surface of the belt. At least one of the projecting wings comprises a projecting rib.