An apparatus for automatically centrifuging test tubes containing biological material including a plurality of centrifuges functionally identical to one another yet independent and adapted to centrifuge test tubes offered to an interface for centrifuging test tubes using a conveying system included in an automatic conveyor of test tubes. The plurality of centrifuges is fitted on a turntable adapted to offer each centrifuge at a suitable loading/unloading point adjacent to the loading/unloading point of the interface. Each centrifuge is provided with a motor adapted to generate the centrifugal motion by setting a rotor in rotation, and a test tube handling device including an arm with a first gripper adapted to load test tubes to be centrifuged and a second gripper adapted to unload centrifuged test tubes, simultaneously to the loading, the arm sliding along a curved guide adapted to generate a forced rotation of the grippers.