An object is to improve the operational reliability of a gas turbine by suppressing thermal stress and thermal deformation acting on the rotor of the gas turbine. The gas turbine has a rotor shaft constructed by arranging, in an axial direction in turn, a plurality of discs each having a plurality of combustion gas-driven moving blades annularly arranged on the peripheral portion and spacers arranged between the discs, and is characterized in that gap portions are formed between a region, on the rotor shaft center portion side, of the above-mentioned discs facing the spacers and spacers adjacent thereto, contact surfaces are formed both of which contact on both a region, on the rotor peripheral side, of the above-mentioned discs facing the spacers and adjacent spacers thereto, and a third flow path leading fluid to the above-mentioned gap portions is provided.