A device for dispensing a plurality of unitary doses of dry powder includes: first and second supports, an indexing mechanism adapted to move the first and second supports, the indexing mechanism and the supports being configured so that in a first dispensing state of the device, the first and second supports are respectively in engagement with and disengaged from the indexing mechanism, in a second dispensing state of the device, the second and first supports are respectively in engagement with and disengaged from the indexing mechanism, and a changeover mechanism for causing the device to pass from the first dispensing state to the second dispensing state, to lock the second support while the device is in the first dispensing state, and to lock the first support while the device is in the second dispensing state.