An elongated sleeve made of a plurality of substantially rigid panels interconnected with one another in folding relationship. When in the stored condition, the sleeve is folded flat. When in condition to be used for its intended purpose, the sleeve is unfolded to form an open ended sleeve closed on the sides. The sleeve is adapted to positively retain and support a collapsible bag at the top while the bag is being filled by filling the interior of the sleeve. Handles are provided in the top edges of the sleeve to facilitate removal of the sleeve from the full bag.