A powder inhaler comprising: a body (10) that is provided with a dispenser orifice at least one reservoir containing a dose of powder for dispensing reservoir-opening means for opening a reservoir on each actuation and a dispersion chamber (70) including an outlet (720) that is connected to said dispenser orifice, and an inlet (710) that is connected to said opening means and that receives the dose of powder from said open reservoir, said dispersion chamber (70) containing at least one movable element (75), such as a ball the inhaler being characterized in that said dispersion chamber (70) includes a ball path (730) having a width that decreases from said inlet (710) in the direction of displacement of said at least one ball (75).
