The invention refers to an inhalation device provided with a dose ring (2, 38, 65) intended for storage and release of substances in powder form such as a drug, comprising a plurality of substantially circular recesses or powder chambers (1, 37, 66) for storing a respective dose of a preloaded powdery substance, and an air channel (7, 43, 43a, 67) or uncovering device (68) for dispensing one dose at a time, wherein an advancing mechanism (5,41) is arranged to feed the dose ring (2, 38, 65) in its direction of rotation one powder chamber (1, 37, 66) at a time. The invention is achieved by that the powder chambers (1, 37, 66) are oriented in the surface of the dose ring (2, 38, 65), that at least one seal (27,29,35) is arranged to seal the dose ring (2, 38, 65) so that the powder chambers (1, 37, 66) are sealed from each other for retaining the doses of powder in the respective powder chambers (1, 37, 66), that the dose ring (2, 38, 65) is arranged so that said powder chambers (1, 37, 66) can be uncovered or opened to at least a portion of an air channel (7, 43, 43a, 67) arranged in the position for the powder chamber (1, 37, 66) which is to dispense a dose of powder, and that the seal (27, 29, 35), at the rotation position for dispensing the dose of powder, is or can be opened to the air channel (7, 43, 67) so that the powder chamber (1, 37, 66) and its content is exposed to, and can pass through, the air channel (7, 43, 43a, 67) by means of an air flow.L'invention concerne un dispositif d'inhalation doté d'une bague de dosage (2, 38, 65) destinée à stocker et à libérer des substances en poudre, telles qu'un médicament, comprenant une pluralité d'évidements ou de chambres de poudre sensiblement circulaires (1, 37, 66) pour stocker une dose correspondante d'une substance en poudre préchargée, et un canal d'air (7, 43, 43a, 67) ou un dispositif non recouvert (68) pour distribuer une dose à la fois, un mécanisme d'avancement (5,41) disposé pour alimenter la bague de dos
