A tape waste collector assembly is suited for use with a belt loop sewing machine having a tape cutter for cutting a length of tape placed on a tape receiving plate into pieces of a predetermined length so that each of the pieces of tape may be sewn on a garment to form a belt loop. The tape waste collector assembly includes an air source, one or more air pipes pneumatically connected to the air source for blowing compressed air supplied from the air source towards the length of tape placed on the tape receiving plate, and a plurality of tape waste collecting elements such as, for example, a hose, a waste box and the like for collecting tape wastes produced when the length of tape is cut by the tape cutter. A controller controls a plurality of solenoid valves to operate the air pipes and the plurality of tape waste collecting elements so that the tape wastes blown off by the air pipes are appropriately collected by the plurality of tape waste collecting elements.