An inhaler for powdery, in particular medical, substances is formed with a suction air channel, which leads to a mouthpiece. The inhaler also has a storage chamber for storing the substance and a linearly moving dosing chamber for apportioning a specified amount of substance from the storage chamber to a transfer point to the suction air flow. The aim of the invention is to obtain a structurally simple solution that makes it possible to eliminate adding an external air flow. To this end, a component of the suction air flow, which is located in the direction of extension of the dosing chamber, empties said dosing chamber.