A turbine rotor of an embodiment includes a rotor body portion having turbine discs in plural stages in an axial direction protruding radially outside from an outer peripheral surface of the rotor body portion over a circumferential direction. The turbine rotor includes a plurality of axial passages, through which a cooling medium flows, formed at the rotor body portion radially outside than a center axis of the turbine rotor and radially inside than an outer peripheral surface of the rotor body portion in the axial direction; an introduction passage introducing the cooling medium into each of the axial passages; and discharge passages that penetrate from each of the axial passages to the outer peripheral surface of the rotor body portion to discharge the cooling medium.