A powder inhaler device having a body provided with a dispenser orifice a plurality of predosed reservoirs each containing a dose of powder for dispensing and reservoir-opening device for opening a reservoir on each actuation. The inhaler device has a dispersion chamber including an inlet connected during inhalation to an open reservoir and receiving the flow of air and of powder from the open reservoir via a delivery channel, and an outlet connected to the dispenser orifice via a dispenser channel. The dispersion chamber including at least one ball that is movable along a ball path in the dispersion chamber, the dispersion chamber including at least one air inlet that is approximately tangential to said ball path, the delivery and dispenser channels extending in a same direction that is substantially perpendicular to the ball path and to the tangential air inlet.
