The piston ring sealing points of a sealing apparatus between the rotor and the housing of a continuous-flow machine each have a piston ring, a cylindrical contact surface, which is directed radially inward, on the housing, as well as an axial stop on the rotor. In this case, the piston ring of the outer piston ring sealing point has a larger external radius and a smaller internal radius than the piston ring of the inner piston ring sealing point. At the same time, the outer piston ring sealing point has a smaller internal radius than the inner piston ring sealing point. Because of the V-shaped arrangement concept, there is no need for a steel ring, shrunk onto the rotor, between the piston ring sealing points.