Abstract: A rotating fluid machine for reversible operation from turbine to pump and from pump to turbine having a simple structure which allows for easy manipulation when reversing operation, and having a low change in efficiency when the machine operates in reverse. The fluid machine includes a bladed rotor containing a rotor spindle, a rotor disk, at least one radial groove, a carrying pin integral to the rotor disk, and at least one rotor blade. The blade, which controls the fluid flow, possesses two identical tongues that extend symmetrically with respect to the axis of the carrying pin and protrude with respect to the rotor disk. The machine possesses an external duct for input of the fluid to the fluid duct. The blade of the carrying pin then rotates in accordance with the toroidal structure of the bladed rotor, allowing the fluid to pass through three passages and to exit by way of a second external duct.