A disposable device for the continuous centrifugal separation of a physiological fluid includes: a fixed axial element; a centrifugation chamber that can rotate around the axis of the element; an inlet channel for the blood to be centrifuged, whose dispensing port is close to the base of the chamber; and an outlet passage for a separated constituent, whose inlet port is close to the other end of the chamber in a concentrated area of one of the separated constituents having the lowest mass density in order to remove it continuously. The chamber takes the form of a long tube. The fixed axial element includes a second outlet passage for a second separated constituent, whose inlet port is close to the end of the chamber opposite the base in a concentrated area of the second separated constituent having the highest mass density in order to remove it continuously.