A fluid dispenser device including at least one individual reservoir (21) containing a single dose of fluid, such as powder, opening means (40) being provided for opening an individual reservoir (21) each time the device is actuated, the device including a dispenser chamber (70) for receiving the dose of fluid contained in a reservoir (21) after said reservoir has been opened, an inhalation endpiece (15), and an inhalation trigger system that comprises a deformable air-chamber (61) that co-operates with said dispenser chamber (70), said dispenser chamber being displaceable between a rest position and an inhalation position, such that during inhalation through said inhalation endpiece (15), said air chamber (61) is deformed, thereby displacing said dispenser chamber from said rest position to said inhalation position.