A powder-delivering device includes a tapered shell received in a toner cartridge near an outlet of the toner cartridge. The tapered shell has a transection area becoming smaller gradually toward the outlet of the toner cartridge. The tapered shell has an outer surface having at least one projection or at least one recess. The projection of the tapered shell has a spiral or linear shape. The projection has an end, which is remote from the outlet of the toner cartridge, stopped against an inner wall of the toner cartridge. Thus, the powder-delivering device of the invention has simple structure and low product costs.