A rolling mill stand and related rolling mill for rolling rod-shaped bodies, even large in size, which meets the requirement of stiffness uniformity of the rolling mill stands in the transversal direction, all the hydraulic capsules being firmly fixed to the external structure of the rolling mill and providing for the side change of the rolls of each stand. The arrangement of rolling rolls and related extensions of each rolling mill stand is such to avoid problems of corrosion and damaging to the extensions themselves and to the reducers due to the drainage of the cooling waters.