Abstract: A device for supporting and holding open the mouth end of a bag during the filling thereof including an elongated, relatively thin, flexible, plastic sheet having hand openings and a series of spaced slots therein and depending locking tabs on one end thereof. Thus, the sheet may be bent into cylindrical form with its edges overlapping and the tabs disposed in those slots which permit the sheet to cylindrically and snugly conform to that of the bag within which it is inserted. When so sleeved within the mouth of a bag, the locking tabs will retain the sheet in assembled position to permit of ready filling thereof, after which the device may be withdrawn and collapsed for reuse.