[Problem] To provide an operation method for noticeably prolonging the life of "rotor" where the impeller and the axial rod are integrated with each other, in mechanical stirring of chrome-containing molten iron. [Means for Resolution] An operation method for mechanically stirring chrome-containing molten iron, which comprises a refining process of mechanically stirring chrome-containing molten iron contained in a refining vessel by the use of an impeller having a rotation axis in the vertical direction where the refining vessel is such that the horizontal cross section of the inner wall thereof is circular around the central axis of the vessel in the vertical direction and the impeller, as integrated with the axial rod covered with a refractory, rotates around the central axis of the axial rod, as the rotation axis thereof, wherein: the stirring mode is regularly or irregularly switched, as selected for each stirring charge, between "concentric stirring mode" of stirring the molten iron in a state where the rotation axis of the impeller is centered in the central axis of the vessel and "eccentric stirring mode" of stirring the molten iron in a state where the rotation axis of the impeller is decentered from the central axis of the vessel.