Gas turbine

A gas turbine comprising a compressor, a combustor and a turbine body operatively connected to the compressor through a rotation shaft, said turbine body being composed of a plurality of rotors formed with turbine discs and movable blades which are arranged in plural stages along an axial direction of the turbine main body, in which a rear shaft is connected to a downstream side of a final stage disc of the gas turbine discs so as to extend rearward from the final stage turbine disc and supported by means of a bearing,

• wherein said rear shaft is formed with a cooling medium supply passage for supplying a cooling medium to the turbine disc and a cooling medium recovery passage for recovering the cooling medium from the turbine disc, and wherein a labyrinth seal is provided between the gas turbine disc and the bearing, said labyrinth seal being formed with a cooling medium supply hole which communicates with the cooling medium supply passage and a cooling medium recovery hole which communicates with the cooling medium recovery passage, and a cooling medium passage is further formed in the rear shaft supported by means of the bearing.