The invention relates to a metering device (1) which can be activated by the user's suction airstream and is intended for the inhalation of a pulverulent substance (2), in particular a medicinal substance, which is disposed in a storage chamber (15) and can be moved out of this chamber, when the mouthpiece-closure cap (7) is removed, by means of a metering chamber (40) of a metering rod (33) into an openable emptying-standby position (B). In particular in order to make it easier to open the metering chamber (40), the invention proposes to provide piston-extending tongues (77) for closing the metering chamber.一種計量裝置(1)，其可藉由使用者之抽吸氣流而被啟動，且用於吸入粉狀物質(2)，尤其是醫藥物質，而該粉狀物質係安置於儲存室(15)中，且可在移除吹口閉合帽(7)時藉助於計量桿(33)之計量室(40)而自此腔室移出，以進入一個可開啟的空出待用位置(B)中。尤其為使該計量室(40)易於開啟，本發明設置了用於閉合計量室的活塞延伸舌狀物(77)。
