Abstract: In a conveyor system of dust containers for using in a building, particularly an apartment house, dust discarded from respective houses is contained in a cylindrical polysheet, which is clipped at separated points to form dust capsules having a smaller diameter than the inner diameter of a vertical chute so that the capsules in the chute are subjected to air resistance. A pressure detector is provided near the bottom of the chute. In response to the output of the pressure detector the quantity of air escaping to the outside from the upper end of the chute is controlled so that the falling speed of the capsule is adjusted to a safe value.